JP7709975B2 - Two-component (2K) curable adhesive composition - Google Patents

Description

The present invention is directed to adhesive compositions that are removable from the particular substrate to which they are applied. More specifically, the present invention relates to curable, removable, two-part (2K) hybrid adhesive compositions.

Adhesive bonds and polymer coatings are commonly used in the assembly and finishing of manufactured items. They are used as an alternative to mechanical fasteners such as screws, bolts and rivets, reducing machining costs and providing a more adaptable bond in the manufacturing process. Adhesive bonds distribute stress evenly, reducing the possibility of fatigue and insulating the joint from corrosive species.

Thus, although adhesives offer many advantages over mechanical fasteners, adhesively bonded articles tend to be difficult to disassemble when practical needs dictate. Adhesive removal by mechanical processes such as sandblasting or wire brushing is often precluded, in part because the adhesive is located between the substrates and is therefore inaccessible or difficult to abrade without destroying the substrate surfaces. Disassembly by application of chemicals and/or elevated temperatures, such as those disclosed in U.S. Pat. No. 4,171,240 (Wong) and U.S. Pat. No. 4,729,797 (Linde et al.), may be effective but can be time consuming and complicated to implement. Furthermore, the aggressive chemicals and harsh conditions required can damage the substrates being separated, rendering them unsuitable for subsequent applications.

With these problems in mind, certain authors have attempted to develop peelable adhesive compositions that act by passing an electric current through the cured composition, thereby destroying the bond at the adhesive/substrate interface.

U.S. Patent No. 7,465,492 (Gilbert) describes a strippable composition comprising a matrix functionality comprising a monomer selected from the group consisting of acrylic, methacrylic, and combinations thereof; a free radical initiator; and an electrolyte, the electrolyte providing the composition with sufficient ionic conductivity to assist in a faradaic reaction in the bond formed between the composition and a conductive surface, thereby allowing the composition to be stripped from the surface.

U.S. Patent Application Publication No. 2007/0269659 (Gilbert) describes a two-interface releasable adhesive composition that (i) includes a polymer and an electrolyte; (ii) facilitates bonding of two surfaces; and (iii) releases from both the anodic and cathodic interfaces in response to a voltage applied across both surfaces to form an anodic and cathodic interface.

U.S. Patent Application Publication No. 2008/0196828 (Gilbert) describes a hot melt adhesive composition comprising a thermoplastic component; and an electrolyte, the electrolyte providing sufficient ionic conductivity to the composition to enable a faradaic reaction in the bond formed between the composition and a conductive surface to allow the composition to be peeled from the surface.

WO 2017/133864 (Henkel AG & Co. KGaA) describes a method for reversibly bonding first and second substrates, at least the first substrate being an electrically non-conductive substrate, comprising a) coating a surface of the electrically non-conductive substrate with a conductive ink; b) applying an electrically releasable hot melt adhesive composition to the conductive ink-coated surface of the first substrate and/or the second substrate; c) contacting the first substrate with the second substrate such that the electrically releasable hot melt adhesive composition is interposed between the two substrates; d) forming an adhesive bond between the two substrates to provide a bonding substrate; and e) applying a voltage to the bonding substrates, thereby substantially weakening the adhesion of at least one interface between the electrically releasable hot melt adhesive composition and the substrate surface.

U.S. Pat. No. 4,171,240 U.S. Pat. No. 4,729,797 U.S. Pat. No. 7,465,492 US Patent Application Publication No. 2007/0269659 US Patent Application Publication No. 2008/0196828 International Application Publication No. 2017/133864

There remains a need in the art to provide adhesive compositions that can be conveniently applied to the surfaces of the substrates to be adhered, and upon curing provide an effective bond within a composite structure that includes the substrates, but that can be effectively peeled from those substrates by readily applying an electrical potential to the cured adhesive.

According to a first aspect of the present invention,
a) epoxy resin,
b) (meth)acrylate monomers,
c) electrolyte;
d) a solubilizing agent; and
e) fillers;
a) a curing agent comprising at least one compound having at least two epoxide reactive groups per molecule;
A curable, peelable, two-part (2K) hybrid adhesive composition is provided that includes: b) an accelerator; and c) a second component that includes a filler.

In an important embodiment of the present invention, the two-part (2K) hybrid adhesive composition comprises:
Based on the weight of the first component,
- 15 to 60% by weight, preferably 15 to 50% by weight, of said epoxy resin;
from 5 to 50% by weight, preferably from 10 to 30% by weight, of said (meth)acrylate monomer;
- 2.5 to 25% by weight, preferably 5 to 20% by weight, of said electrolyte;
- 0.5 to 20% by weight, preferably 1 to 15% by weight, of said solubilizer; and
the filler;
a first component comprising:
Based on the weight of the second component,
a curing agent consisting of at least one compound having at least two epoxide reactive groups per molecule;
0.1 to 15% by weight, preferably 2 to 10% by weight, of an accelerator; and
the filler,
a second component comprising:

In the first component of the adhesive composition, the electrolyte is 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium methylsulfate, 1-hexyl-3-methylimidazolium 2-(2-fluoroanilino)-pyridinate, 1-hexyl-3-methylimidazolium imide, 1-butyl-1-methylpyrrolidinium 2-(2-fluoroanilino)-pyridinate, 1-butyl-1-methyl-pyrrolidinium imide, trihexyl(tetradecyl)phospholium 2-(2-fluoroanilino)-pyridinate, cyclohexyltrimethylammonium bis(trifluoromethyl sulfonyl)imide, di(2-hydroxyethyl)ammonium trifluoroacetate, N,N-dimethyl(2-hydroxyethyl)ammonium octanoate, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, N-ethyl-N-N-N-N-tetramethylguanidinium trifluoromethanesulfonate, guanidinium trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-hydroxymethylpyridinium ethylsulfate, 1-butyl-1-methylpyrrolidinium Mubis(trifluoromethylsulfonyl)imide, 1-butyl-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, 3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-ethyl-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium tetrachloride It is preferably selected from the group consisting of tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazole, 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium tris(pentafluoroethyl)trifluorophosphate, trihexyl(tetradecyl)phosphonium tetrafluoroborate and mixtures thereof. It is particularly preferable to use at least one of 1-ethyl-3-methylimidazolium methanesulfonate and 1-ethyl-3-methylimidazolium methylsulfate.

Alternatively or in addition to the above mentioned selection of electrolytes in this first component, the solubilizer is preferably selected from polyphosphazenes; polymethylene sulfides; polyoxyalkylene glycols; polyethyleneimines; silicone surfactants and fluorosilicone surfactants; copolymers of functionalized polyalkylsiloxanes and epoxy resins; polyhydric alcohols; and sugars.

In the second component of the composition, the curing agent preferably comprises at least one polyamine having at least two amine hydrogens reactive with epoxy groups, the polyamine further comprising primary amine groups and/or secondary amine groups and characterized by an equivalent weight of 150 g/eq or less per primary or secondary amine group. In this regard, the use of ether group-containing aliphatic primary polyamines is particularly preferred.

Apart from or in addition to the above mentioned selection of the hardener of the second component of the composition, it is preferred that said accelerator is selected from the group consisting of tertiary amines, quaternary ammonium salts, amidines, guanidines and mixtures thereof. It is noted that it is particularly preferred to employ at least one accelerator selected from imidazole, methylimidazole, benzyldimethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene and 1,4-diazabicyclo(2,2,2)octane.

According to a second aspect of the present invention,
A bonded structure is provided that includes: a first material layer having an electrically conductive surface; and a second material layer having an electrically conductive surface, wherein a cured peelable two-part (2K) hybrid adhesive composition as defined herein and in the appended claims is disposed between the first and second material layers.

According to a third aspect of the present invention there is provided a method for delaminating a bonded structure as defined herein and in the appended claims, comprising the steps of:
i) applying a voltage across both surfaces to form an anodic interface and a cathodic interface; and
ii) peeling said surfaces apart.
Step i) of this method preferably comprises
a) an applied voltage of 0.5 to 200 V; and
b) a voltage applied for between 1 second and 60 minutes.

FIG. 1a shows a joint structure according to a first embodiment of the present invention. FIG. 1b shows a joint structure according to a second embodiment of the invention. FIG. 2a shows the initial delamination of the structure of the first embodiment upon passing an electric current across it. FIG. 2b shows the initial delamination of the structure of the second embodiment upon passing an electric current across it. FIG. 3a shows the peeling when different potentials were applied for 20 minutes. FIG. 3b shows the peel over time at 75V. FIG. 4 shows the stability over time of a composition according to the invention.

<Definition>
As used herein, the singular forms "a,""an," and "the" include plural referents unless the context clearly indicates otherwise.

As used herein, the terms "comprising," "comprises," and "comprised of" are synonymous with "including," "includes," "containing," or "contains," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps.

As used herein, the term "consisting" excludes any elements, components, members or method steps not specified.

When amounts, concentrations, dimensions and other parameters are expressed in the form of ranges, preferred ranges, upper values, lower values, or preferred upper values and limits, any range obtained by combining any upper value or preferred value with any lower value or preferred value is to be understood as specifically disclosed, regardless of whether the resulting range is expressly stated in the context.

Furthermore, in accordance with standard understanding, a weight range expressed as being "0 to x" specifically includes 0% by weight. The component defined by said range may be absent from the composition or may be present in the composition in an amount up to x% by weight.

The terms "preferred," "preferably," "desirable," and "particularly" are used frequently herein to refer to embodiments of the present disclosure that may afford certain advantages, under particular circumstances. However, the recitation of one or more preferred, preferred, desirable, or particular embodiments does not imply that other embodiments are not useful, and is not intended to exclude such other embodiments from the scope of the present disclosure.

In this application, the word "may" is used in a permissive (i.e., possible) rather than mandatory sense.

As used herein, room temperature is 23° C. plus or minus 2° C. As used herein, "ambient conditions" refers to the temperature and pressure surrounding the composition or coating layer or substrate on which the coating layer is disposed.

A "two-component (2K) composition" in the context of the present invention is understood to be a composition in which the first component (A) and the second component (B) must be stored in separate containers due to their (high) reactivity. The two components are mixed only immediately before application and then react, typically without additional activation, to form bonds, thereby forming a polymer network. Here, higher temperatures may be applied to accelerate the crosslinking reaction.

As used herein, the term "peelable" means that after the adhesive has cured, the adhesive strength is weakened by at least 50% by application of a potential of 10V to 75V for 1 second to 60 minutes. The curable adhesive is applied between the two substrates to be adhesively bonded such that a current flows through the adhesive bond line. The adhesive strength is measured by a Tensile Lap Shear (TLS) test according to Adhesives - Determination of the Tensile Lap Shear Strength of Bonded Assemblies - according to EN 1465:2009 (German version) performed at room temperature. The adhesive overlap is 25 mm x 10 mm and the adhesive thickness is about 150 μm.

As used herein, the term "monomer" means a substance that can undergo a polymerization reaction to contribute a building block to the chemical structure of a polymer. As used herein, the term "monofunctional" means having one polymerizable site. As used herein, the term "multifunctional" means having two or more polymerizable sites.

As used herein, the term "equivalents (eq.)" refers, as is usual in chemical notation, to the relative number of reactive groups present in a reaction.

The term "electrolyte" is used herein in accordance with its standard meaning in the art as a material that contains free ions capable of conducting electricity by the movement of electrically charged charge carrier species. The term is intended to encompass molten, liquid, semi-solid, and solid electrolytes in which at least one cationic or anionic component of the electrolyte structure is essentially free to move and thus act as a charge carrier.

The curable adhesive compositions of the present invention and the resulting cured adhesives have "electrolyte functionality" in that the adhesive material allows for the conduction of ions, anions or cations, or both. Electrolyte functionality is understood to result from the ability of the compositions and curable adhesives to solvate ions of at least one polarity.

As used herein, "(meth)acrylic" is an abbreviation for "acrylic" and/or "methacrylic." Thus, the term "(meth)acrylamide" refers collectively to acrylamide and methacrylamide.

As used herein, a "C _1- C _n alkyl" group refers to a monovalent group containing 1 to n carbon atoms, which is an alkane group, including linear and branched organic groups. Thus, a "C _1- C ₃₀ alkyl" group refers to a monovalent group containing 1 to 30 carbon atoms, which is an alkane group, including linear and branched organic groups. Examples of alkyl groups include, but are not limited to, methyl; ethyl; propyl; isopropyl; n-butyl; isobutyl; sec-butyl; tert-butyl; n-pentyl; n-hexyl; n-heptyl; and 2-ethylhexyl. In the present invention, such alkyl groups may be unsubstituted or substituted with one or more substituents, such as halo, nitro, cyano, amido, amino, sulfonyl, sulfinyl, sulfanyl, sulfoxy, urea, thiourea, sulfamoyl, sulfamido, and hydroxy. Where applicable, preferences for a given substituent are described herein. However, in general, preference should be given to alkyl groups containing 1 to 18 carbon atoms (C1 _{- C18} alkyl), such as alkyl groups containing 1 to 12 carbon atoms (C1 _{- C12} alkyl) or alkyl groups containing 1 to 6 carbon atoms (C1 _{- C6} alkyl).

The term "C _{1 -C 18} hydroxyalkyl" as used herein refers to a HO-(alkyl) group having 1 to 18 carbon atoms, where the point of attachment of the substituent is through the oxygen atom and the alkyl group is as defined above.

An "alkoxy group" refers to a monovalent group represented by -OA, where A is an alkyl group, non-limiting examples of which are methoxy, ethoxy, and isopropyloxy. As used herein, the term "C _1- C ₁₈ alkoxyalkyl" refers to an alkyl group having an alkoxy substituent, as defined above, where the (alkyl-O-alkyl ) portion contains a total of 1 to 18 carbon atoms. Such groups include methoxymethyl (-CH ₂ OCH ₃ ), 2-methoxyethyl (-CH ₂ CH ₂ OCH ₃ ), 2-ethoxyethyl, and the like.

The term "C2 _{- C4} alkylene," as used herein, is defined as a saturated divalent hydrocarbon radical having from 2 to 4 carbon atoms.

The term "C3 _{- C30} cycloalkyl" is understood to mean an optionally substituted saturated, monocyclic, bicyclic or tricyclic hydrocarbon group having from 3 to 30 carbon atoms. In general, attention should be paid to the selection of cycloalkyl groups containing from 3 to 18 carbon atoms (C3 _{- C18} cycloalkyl groups). Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantane, and norbornane.

As used herein, the group "C6 _{- C18} aryl" used alone or as part of a larger moiety - as in "aralkyl group" - refers to optionally substituted monocyclic, bicyclic and tricyclic ring systems in which the monocyclic ring system is aromatic or in which at least one of the rings of the bicyclic or tricyclic ring system is aromatic. Bicyclic and tricyclic ring systems include benzo-fused 2-3 membered carbocyclic rings. Exemplary aryl groups include phenyl; (C1 _{- C4} ) alkylphenyl, such as tolyl and ethylphenyl; indenyl; naphthalenyl, tetrahydronaphthyl, tetrahydroindenyl; tetrahydroanthracenyl; and anthracenyl. The choice of phenyl group may be noted.

As used herein, "C2 _{- C20} alkenyl" means a hydrocarbyl group having from 2 to 20 carbon atoms and at least one unit of ethylenic unsaturation. Alkenyl groups may be straight chained, branched or cyclic and may be optionally substituted. The term "alkenyl" also encompasses groups having "cis" and "trans" configurations, or, alternatively, "E" and "Z" configurations, as will be appreciated by those skilled in the art. However, care should be taken to generally select unsubstituted alkenyl groups containing from 2 to 10 ( _C2-10 ) or 2 to 8 ( _C2-8 ) carbon atoms. Examples of said C2 _{- C12} alkenyl groups include, but are not limited to, -CH= _CH2 ; -CH=CHCH3; -CH2CH= _CH2 ; -C(= _CH2 )( _CH3 ); -CH= _{CHCH2CH3 ; -CH2CH} = _CHCH3 ; _-CH2CH2CH = _CH2 ; -CH=C( _CH3 ) ₂ ; _-CH2C (= _CH2 )(CH3 _{) ; -C} ( _{= CH2} ) _{CH2CH3 ;} -C( _CH3 ) _{= CHCH3} ; -C( _CH3 ) _CH = _{CH2 ;} -CH= _CHCH2CH2CH3 ; _-CH2CH =CHCH2CH3 _{; -CH2CH 2CH} = _CHCH3 ; _{-CH2CH2CH2CH =CH2;} -C( _{= CH2} )CH2CH2CH3; -C( _CH3 )=CHCH2CH3; _{-CH( CH3 ) CH} =CHCH; -CH( _CH3 ) _CH2CH = _CH2 ; -CH2CH=C( _CH3 ) ₂ ; 1-cyclopent-1-enyl; 1 _- cyclopent- _{2 -} enyl; 1-cyclopent- ₃ -enyl; 1-cyclohex-1-enyl; 1-cyclohex-2-enyl; and 1-cyclohex-3-enyl.

As used herein, "alkylaryl" refers to an alkyl-substituted aryl group, and "substituted alkylaryl" refers to an alkylaryl group further bearing one or more substituents as defined above. Additionally, as used herein, "aralkyl" refers to an alkyl group substituted with an aryl group as defined above.

As used herein, the term "hetero" refers to a group or moiety that includes one or more heteroatoms, such as N, O, Si, and S. Thus, for example, "heterocycle" refers to a cyclic group having, for example, N, O, Si, or S as part of the ring structure. "Heteroalkyl," "heterocycloalkyl," and "heteroaryl" moieties refer to alkyl, cycloalkyl, and aryl groups, as defined herein, that include N, O, Si, or S, respectively, as part of their structure.

As used herein, the term "epoxide" refers to a compound characterized by the presence of at least one cyclic ether group, i.e., a group in which an ether oxygen atom is bonded to two adjacent carbon atoms, thereby forming a cyclic structure. The term is intended to encompass monoepoxide compounds, polyepoxide compounds (having two or more epoxy groups), and epoxide-terminated prepolymers. The term "monoepoxide compound" is intended to indicate an epoxide compound having one epoxy group. The term "polyepoxide compound" is intended to indicate an epoxide compound having at least two epoxy groups. The term "diepoxide compound" is intended to indicate an epoxide compound having two epoxy groups.

The epoxide may be unsubstituted or inertly substituted. Exemplary inert substituents include chlorine, bromine, fluorine and phenyl.

As used herein, a "primary amino group" refers to an _NH2 group bonded to an organic group, and a "secondary amino group" refers to an NH group bonded to two organic groups, both of which may also be part of a ring. Thus, the term "tertiary amine" refers to a nitrogen having a moiety where the nitrogen atom is not bonded to a hydrogen atom. As used herein, the term "amine hydrogen" refers to the hydrogen atom of primary and secondary amino groups.

As used herein, the term "equivalent weight" means the molecular weight divided by the number of the function. Thus, "epoxy equivalent weight" (EEW) is the weight in grams of a resin containing one equivalent of epoxy.

"Amine equivalent" is a calculation (g/eq.) derived from the amine value, which is determined by titrating the amine acetate ion with a dilute, typically 1N, solution of hydrochloric acid. For pure substances, the amine value can be calculated using the pure compound and the molecular weight of KOH (56.1 g/mol).

As used herein, the term "Lewis acid" refers to a molecule or ion - often called an electrophile - that can combine with another molecule or ion by forming a covalent bond with two electrons from the second molecule or ion. Thus, Lewis acids are electron acceptors.

Molecular weights referred to herein can be determined by gel permeation chromatography (GPC) using polystyrene calibration standards in accordance with ASTM 3536.

The viscosities of the compositions described herein are measured using an Anton Paar viscometer, model MCR301, at standard conditions of 25°C and 50% relative humidity (RH), unless otherwise specified. The viscometer is calibrated and serviced once a year. Calibration is performed using specific oils of known viscosity varying from 5,000 cps to 50,000 cps (parallel plate PP25, 23°C, shear rate 1 ( 1/s ) ). Measurements of the compositions according to the invention are performed using parallel plate PP20 at different shear rates from 1.5 (1/s) to 100 (1/s).

Detailed Description of the Invention
The two-part (2K) composition of the present invention is characterized in that fillers are present in both components. The composition of the fillers in each component is determined independently and may be the same or different in each component. Furthermore, the fillers in each component may be composed of conductive fillers, non-conductive fillers or mixtures thereof.

In general, there is no intention to limit the shape of the particles employed as the conductive filler, and needle-shaped, spherical, elliptical, cylindrical, bead-shaped, cubic, or plate-shaped particles may be used alone or in combination. It is further contemplated that aggregates of two or more types of particles may be used. Similarly, there is no intention to limit the size of the particles employed as the conductive filler. However, conventionally, such conductive fillers have an average volume particle size of 1 to 500 μm, e.g., 1 to 200 μm, as measured by laser diffraction/scattering methods.

Exemplary conductive fillers include, but are not limited to, silver; copper; gold; palladium; platinum; nickel; gold or silver coated nickel; carbon black; carbon fibers; graphite; aluminum; indium tin oxide; silver coated copper; silver coated aluminum; metal coated glass spheres; metal coated fillers; metal coated polymers; silver coated fibers; silver coated spheres; antimony doped tin oxide; conductive nanospheres; nano silver; nano aluminum; nano copper; nano nickel; carbon nanotubes; and mixtures thereof. Particulate silver and/or carbon black are preferably used as the conductive filler.

In certain important embodiments, the conductive filler should be present in the composition in an amount of 0-10% by weight, for example up to 5% by weight, based on the total weight of the composition.

In general, there is no intention to limit the shape of the particles employed as the non-conductive filler, and needle-shaped, spherical, elliptical, cylindrical, bead-shaped, cubic, or plate-shaped particles may be used alone or in combination. It is further contemplated that aggregates of two or more types of particles may be used. Similarly, there is no intention to limit the size of the particles employed as the non-conductive filler. However, conventionally, such non-conductive fillers have an average volumetric particle size of 0.1 to 1500 μm, e.g., 1 to 1000 μm, or 1 to 500 μm, as measured by laser diffraction/scattering methods.

Exemplary non-conductive fillers include, but are not limited to, calcium carbonate, calcium oxide, calcium hydroxide (lime powder), precipitated and/or pyrogenic silicic acid, zeolites, bentonite, wollastonite, magnesium carbonate, diatomaceous earth, barium sulfate, alumina, clay, talc, sand, quartz, flint, mica, glass beads, glass powder, and other minerals. Short fibers such as glass fibers, glass filaments, polyacrylonitrile, carbon fibers, polyethylene fibers, etc. may also be added.

The pyrogenic and/or precipitated silicic acids preferably have a BET surface area of 10 to 90 m ² /g. If they are used, they do not cause a further increase in the viscosity of the composition according to the invention, but contribute to the strengthening of the set composition.

It is also conceivable to use pyrogenic and/or precipitated silicic acids as fillers, which have a higher BET surface area, preferably between 100 and 250 m ² /g. Due to the higher BET surface area, the effect of strengthening the setting composition is achieved with a smaller proportion by weight of silicic acid.

Also suitable as non-conductive fillers are hollow spheres with a mineral or plastic shell. These may be, for example, hollow glass spheres commercially available under the trade name Glass Bubbles®. Plastic-based hollow spheres such as Expancel® or Dualite® can also be used and are described in EP 0 520 426 B1. These consist of inorganic or organic material and have a diameter of less than or equal to 1 mm, preferably less than or equal to 500 μm, more preferably between 100 and 200 μm, respectively.

Non-conductive fillers that impart thixotropy to the composition may be preferred in many applications. Such fillers are also described as rheological aids, e.g., hydrogenated castor oil, fatty acid amides, or swellable plastics such as PVC.

In a highly preferred embodiment, the filler of the first component and the filler of the second component may be the same or different and are independently selected from the group consisting of calcium carbonate, calcium oxide, talcum, fumed silica, silica, wollastonite, barium sulfate, glass beads, and mixtures thereof.

The above fillers are preferred because they impart desirable properties to the composition, such as improved adhesion properties (wollastonite); improved aging properties and moisture removal (barium sulfate and calcium carbonate); optimal spacing (glass beads) and improved hydrophobicity and rheology (fumed silica).

In a highly preferred embodiment, the composition according to the invention comprises fumed silica as a filler.

Hydrophobicity may be required for the electrolyte to dissolve in the composition and avoid phase separation. Preferred fillers, especially fumed silica, impart the necessary hydrophobicity to the composition, thus improving electrolyte solubility and preventing phase separation. Furthermore, technical data indicates that the presence of non-conductive fillers improves the initial adhesive performance of the composition.

The desired viscosity of each component of the composition, and the desired viscosity of the curable composition formed upon combining the two components, can determine the amount of filler used. With this latter consideration in mind, the total amount of filler (both conductive and non-conductive) present in the composition should not prevent the composition from being easily extruded from a suitable dispensing device such as a tube. Conventionally, it is desirable for such extrudable curable compositions to have a viscosity of 3000 to 150,000, preferably 40,000 to 80,000 mPas, or even 50,000 to 60,000 mPas.

It is preferred that the first component of the composition comprises 1-40% by weight of filler, based on the weight of said first component. It is preferred that the filler constitutes 1-25% by weight of said first component, for example 1.5-18% by weight. Independently of this optional statement, it is preferred that the second component of the composition comprises 10-30% by weight, preferably 15-13% by weight of filler, based on the weight of said second component.

<First component of two-liquid composition>
The first component of the two-part (2K) composition includes an epoxy resin; a (meth)acrylate monomer; an electrolyte; a solubilizer; and a filler.

<Epoxy resin>
The first component of the composition comprises an epoxy resin which is typically present in an amount of 15 to 60% by weight based on the weight of said first component. It is preferred that the epoxy resin comprises 15 to 50% by weight of said first component, more preferably 20 to 45% by weight, for example 25 to 40% or 28 to 39% by weight.

The above amounts of epoxy resin are preferred because an amount of epoxy resin greater than 60% can be detrimental to the adhesiveness and flexibility of the composition, while a small amount, typically less than 15%, can lead to a high shrinkage rate.

Epoxy resins as used herein may include monofunctional epoxy resins, multifunctional (multi, or poly) epoxy resins, and combinations thereof. Epoxy resins may be pure compounds, as well as mixtures of epoxy-functional compounds, including mixtures of compounds having different numbers of epoxy groups per molecule. Epoxy resins may be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic, and may be substituted. Additionally, epoxy resins may be monomeric or polymeric.

Although not intended to limit the invention, exemplary monoepoxide compounds include the following: alkylene oxides; epoxy-substituted alicyclic hydrocarbons, such as cyclohexene oxide, vinylcyclohexene monoxide, (+)-cis-limonene oxide, (+)-cis,trans-limonene oxide, (-)-cis,trans-limonene oxide, cyclooctene oxide, cyclododecene oxide, and α-pinene oxide; epoxy-substituted aromatic hydrocarbons; monoepoxy-substituted alkyl ethers of monohydric alcohols or phenols, such as glycidyl ethers of aliphatic, alicyclic, and aromatic alcohols; monoepoxy-substituted alkyl esters of monocarboxylic acids, such as glycidyl esters of aliphatic, alicyclic, and aromatic monocarboxylic acids; monoepoxy-substituted alkyl esters of polycarboxylic acids, in which the other carboxy group is esterified with an alkanol; alkyl and alkenyl esters of epoxy-substituted monocarboxylic acids; epoxy alkyl ethers of polyhydric alcohols, in which the other OH group is esterified or etherified with a carboxylic acid or alcohol; and monoesters of polyhydric alcohols and epoxy monocarboxylic acids, in which the other OH group is esterified or etherified with a carboxylic acid or alcohol.

By way of example, the following glycidyl ethers may be mentioned as being particularly suitable monoepoxide compounds for use herein: methyl glycidyl ether; ethyl glycidyl ether; propyl glycidyl ether; butyl glycidyl ether; pentyl glycidyl ether; hexyl glycidyl ether; cyclohexyl glycidyl ether; octyl glycidyl ether; 2-ethylhexyl glycidyl ether; aryl glycidyl ether; benzyl glycidyl ether; phenyl glycidyl ether; 4-tert-butylphenyl glycidyl ether; 1-naphthyl glycidyl ether; 2-naphthyl glycidyl ether; 2-chlorophenyl glycidyl ether; 4-chlorophenyl glycidyl ether; 4-bromophenyl glycidyl ether; 2,4,6-trichlorophenyl glycidyl ether; 2,4,6-tribromophenyl glycidyl ether; pentafluorophenyl glycidyl ether; o-cresyl glycidyl ether; m-cresyl glycidyl ether; and p-cresyl glycidyl ether.

In an embodiment, the monoepoxide compound has the following formula (I):

wherein R ^w , R ^x , R ^y and R ^z may be the same or different and are independently selected from hydrogen, a halogen atom, a C _1-8 alkyl group, a C _3-10 cycloalkyl group, _{a C 2-12 alkenyl} group, _a C _6-18 aryl group or _a C _7-18 aralkyl group, with the proviso that at least one of ^{R y} and _{R z} is not hydrogen.
Complies with.

Preferably, R ^w , R ^x and R ^y are hydrogen and R ^z is a phenyl group or a C _{1 -C 8} alkyl group, more preferably a C _{1 -C 4} alkyl group.

For this embodiment, exemplary monoepoxides include: ethylene oxide; 1,2-propylene oxide (propylene oxide); 1,2-butylene oxide; cis-2,3-epoxybutane; trans-2,3-epoxybutane; 1,2-epoxypentane; 1,2-epoxyhexane; 1,2-heptylene oxide; decene oxide; butadiene oxide; isoprene oxide; and styrene oxide.

The present invention refers to the use of at least one monoepoxide compound selected from the group consisting of ethylene oxide; propylene oxide; cyclohexene oxide; (+)-cis-limonene oxide; (+)-cis, trans-limonene oxide; (-)-cis, trans-limonene oxide; cyclooctene oxide; and cyclododecene oxide.

Again, without intending to limit the invention here, suitable polyepoxide compounds may be liquid, solid, or in solution in a solvent. Furthermore, such polyepoxide compounds should have an epoxy equivalent weight of 100 to 700 g/eq, for example 120 to 320 g/eq. Furthermore, diepoxide compounds having an epoxy equivalent weight of less than 500 g/eq, or even less than 400 g/eq, are generally preferred. This is mainly from a cost perspective, since in their production, low molecular weight epoxy resins require limited processing in purification.

As examples of types or groups of polyepoxide compounds which can be polymerized in the present invention, mention may be made of: glycidyl ethers of polyhydric alcohols and polyhydric phenols; glycidyl esters of polycarboxylic acids; and epoxidized polyethylenically unsaturated hydrocarbons, esters, ethers and amides.

Suitable diglycidyl ether compounds may be aromatic, aliphatic or cycloaliphatic in nature and as such are derivable from dihydric phenols and dihydric alcohols, and useful classes of such diglycidyl ethers are the diglycidyl ethers of aliphatic and cycloaliphatic diols, such as 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,12-dodecanediol, cyclopentanediol and cyclohexanediol; bisphenol A-based diglycidyl ethers; bisphenol F diglycidyl ethers; diglycidyl o-phthalate, diglycidyl isophthalate and diglycidyl terephthalate; polyalkylene glycol-based diglycidyl ethers, particularly polypropylene glycol diglycidyl ethers; and polycarbonate diol-based glycidyl ethers. Other suitable diepoxides that may be mentioned include diepoxides of doubly unsaturated fatty acid C ₁ -C ₁₈ alkyl esters; butadiene diepoxide; polybutadiene diglycidyl ether; vinylcyclohexene diepoxide; and limonene diepoxide.

Further exemplary polyepoxide compounds include, but are not limited to, glycerol polyglycidyl ether; trimethylolpropane polyglycidyl ether; pentaerythritol polyglycidyl ether; diglycerol polyglycidyl ether; polyglycerol polyglycidyl ether; and sorbitol polyglycidyl ether.

And examples of highly preferred polyepoxide compounds include bisphenol A epoxy resins such as ^DER 331 and ^DER 383, bisphenol F epoxy resins such as ^DER 354, bisphenol A/F epoxy resin blends such as DER 353, aliphatic glycidyl ethers such as ^DER 736, polypropylene glycol diglycidyl ethers such as ^DER 732, solid bisphenol A epoxy resins such as ^DER 661 and ^{DER 664UE} , solutions of bisphenol A solid epoxy resins such as ^DER 671-X75, epoxy novolac resins such as ^DEN 438, brominated epoxy resins such as ^DER 542, castor oil triglycidyl ethers such as ERISYS ^GE -35H, ERISYS GE-35H, and the like ^. Polyglycerol-3-polyglycidyl ethers, such as GE-38, and sorbitol glycidyl ethers, such as ERISYS ^™ GE-60.

Alternatively, the first component of the composition may, in certain embodiments, be a compound of the formula:


[In the formula,
Each R is independently selected from methyl or ethyl; and
n is 1 to 10.
The glycidoxyalkylalkoxysilane may include a glycidoxyalkylalkoxysilane having the formula:

Exemplary silanes include, but are not limited to, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxyethyltrimethoxysilane, gamma-glycidoxymethyltrimethoxysilane, gamma-glycidoxymethyltriethoxysilane, gamma-glycidoxyethyltriethoxysilane, gamma-glycidoxypropyltriethoxysilane; and 8-glycidoxyoctyltrimethoxysilane. When present, it is desirable for the epoxide-functional silanes to constitute less than 20% by weight, preferably less than 10% by weight or less than 5% by weight, based on the total weight of the epoxide compounds.

The present invention also does not preclude the first component of the curable composition from further comprising one or more cyclic monomers selected from the group consisting of oxetanes; cyclic carbonates; cyclic anhydrides; and lactones. The disclosures of the following references may be useful in disclosing suitable cyclic carbonate-functional compounds: U.S. Pat. No. 3,535,342; U.S. Pat. No. 4,835,289; U.S. Pat. No. 4,892,954; British Patent Application Publication No. 1,485,925; and European Patent Application Publication No. 0 119 840. However, it is desirable for such cyclic comonomers to constitute less than 20% by weight, preferably less than 10% by weight or less than 5% by weight, based on the total weight of the epoxide compounds.

<(Meth)acrylate Monomer>
The first component of the composition typically comprises a (meth)acrylate monomer which will be present in an amount of 5 to 50% by weight based on the weight of said first component. It is preferred that the (meth)acrylate monomer constitutes 7 to 40% by weight of said first component, for example 10 to 30% by weight or 15 to 27% by weight.

The amount of (meth)acrylate monomer is preferably the above amount, since if it exceeds 50%, the shrinkage rate of the composition may increase, while if it is a low amount, mainly less than 5%, the flexibility of the composition may decrease.

In an alternative presentation of the compositional options, not intended to be mutually exclusive with those presented above, the weight ratio of epoxy resin to (meth)acrylate monomer is in the range of 4:1 to 1:1, preferably 4:1 to 2:1, e.g., 4:1 to 2.5:1.

There is no intent to limit the (meth)acrylate monomers having utility herein, and it is believed that the (meth)acrylate monomer may be any ester of acrylic or methacrylic acid known in the art. Thus, exemplary (meth)acrylic monomers include, but are not limited to, the following:
C1-C18 alkyl esters of (meth)acrylic acid, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate (all isomers), hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, and _{n -} stearyl (meth)acrylate;
C3 _{- C18} cycloalkyl esters of (meth)acrylic acid, such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate;
C6 _{- C18} aryl esters of (meth)acrylic acid, such as phenyl (meth)acrylate and tolyl (meth)acrylate;
C7 _{- C24} aralkyl esters of (meth)acrylic acid, such as benzyl (meth)acrylate;
C1 _{- C18} alkoxyalkyl esters of (meth)acrylic acid, such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 3-methoxybutyl (meth)acrylate;
Fluorine-containing C 1-C 18 alkyl esters of (meth)acrylic acid, such as trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, _2- perfluorodecylethyl (meth)acrylate and ₂ -perfluorohexadecylethyl (meth)acrylate;
C1 _{- C18} hydroxyalkyl esters of (meth)acrylic acid, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate and pentaerythritol tri(meth)acrylate;
di/poly-esters of di/poly-functional alcohols such as ethylene glycol di(meth)acrylate, 1,3 or 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate and trimethylolpropane tri(meth)acrylate;
C1 _{- C18} aminoalkyl esters of (meth)acrylic acid, such as 2-aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and (meth)acryloxyethoxyethylamine;
C1 _{- C18} alkoxysilyl-containing alkyl esters of (meth)acrylic acid, such as γ-(meth)acryloyloxypropyltrimethoxysilane;
an ethylene oxide or propylene oxide adduct of (meth)acrylic acid; and
(Meth)acrylate esters formed with alcohols bearing other functional groups, such as tetrahydrofurfuryl (meth)acrylate.

For the sake of completeness, it is not excluded that the first component of the composition comprises a macromonomer component consisting of one or more oligomers selected from the group consisting of urethane (meth)acrylates, polyester (meth)acrylates and polyether (meth)acrylates. However, such oligomeric compounds based on repeating urethane, ester and ether subunits, which may be monofunctional or polyfunctional with respect to the polymerizable (meth)acrylate functionality, should not usually constitute more than 30% by weight of the total (meth)acrylate monomers in said first component.

As known in the art, urethane (meth)acrylate oligomers can be prepared by reacting a multifunctional (meth)acrylate having hydroxyl groups with a polyisocyanate as defined herein above. In particular, the multifunctional (meth)acrylate having hydroxyl groups can be selected from the group consisting of 2-hydroxyethyl (meth)acrylate; 2-hydroxyisopropyl (meth)acrylate; 4-hydroxybutyl (meth)acrylate; hydroxyethyl caprolactone (meth)acrylate; pentaerythritol tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; dipentaerythritol penta(meth)acrylate; dipentaerythritol hexa(meth)acrylate; and combinations thereof.

Suitable polyester (meth)acrylate oligomers are obtained by reacting (meth)acrylic acid with polyesters prepared from polybasic acids or their anhydrides and polyhydric alcohols. Examples of polybasic acids include, but are not limited to, phthalic acid, succinic acid, adipic acid, glutaric acid, sebacic acid, isosebacic acid, tetrahydrophthalic acid, hexahydrophthalic acid, dimer acid, trimellitic acid, pyromellitic acid, pimelic acid, and azelaic acid. Examples of polyhydric alcohols include, but are not limited to, 1,6-hexanediol, diethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, neopentyl glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol.

As known in the art, polyether (meth)acrylate oligomers can be obtained by transesterification between polyethers and (meth)acrylate esters such as ethyl methacrylate. Exemplary polyethers include polyethers obtained from ethoxylated or propoxylated trimethylolpropane, pentaerythritol, etc., or polyetherified 1,4-propanediol, etc.

In a preferred embodiment, the first component is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, tolyl (meth)acrylate, benzyl (meth)acrylate, 2-methyl (meth)acrylate, Toxicethyl (meth)acrylate; 3-methoxybutyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate; 2-hydroxypropyl (meth)acrylate; stearyl (meth)acrylate; glycidyl (meth)acrylate; isobornyl (meth)acrylate; 2-aminoethyl (meth)acrylate; γ-(meth)acryloyloxypropyltrimethoxysilane; (meth)acrylic acid-ethylene oxide adduct; trifluoromethylmethyl (meth)acrylate; 2-trifluoromethylethyl (meth)acrylate; 2-perfluoroethylethyl (meth)acrylate; 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate; 2-perfluoroethyl (meth)acrylate t; Perfluoromethyl (meth)acrylate; Diperfluoromethyl methyl (meth)acrylate; 2-perfluoromethyl-2-perfluoroethyl methyl (meth)acrylate; 2-perfluorohexylethyl (meth)acrylate; 2-perfluorodecylethyl (meth)acrylate; 2-perfluorohexadecylethyl (meth)acrylate; Ethoxylated trimethylolpropane triacrylate; Trimethylolpropane trimethacrylate; Dipentaerythritol monohydroxypentaacrylate; Pentaerythritol triacrylate; Ethoxylated trimethylolpropane triacrylate; 1,6-Hexanediol diacrylate; Neopentyl glycol diacrylate; Pentaerythritol Contains at least one (meth)acrylate monomer selected from the group consisting of tetraacrylate; 1,2-butylene glycol diacrylate; trimethylolpropane ethoxylate tri(meth)acrylate; glyceryl propoxylate tri(meth)acrylate; trimethylolpropane tri(meth)acrylate; dipentaerythritol monohydroxypenta(meth)acrylate; tripropylene glycol di(meth)acrylate; neopentyl glycol propoxylate di(meth)acrylate; 1,4-butanediol di(meth)acrylate; triethylene glycol di(meth)acrylate; butylene glycol di(meth)acrylate and ethoxylated bisphenol A di(meth)acrylate.

Good results have been obtained when the first component comprises at least one (meth)acrylate monomer selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, isobornyl (meth)acrylate, ethoxylated trimethylolpropane triacrylate and trimethylolpropane triacrylate, and mixtures thereof.

The above (meth)acrylate monomers are preferred because the size of the monomers is believed to result in the formation of an ideal polymer network, enhancing ion transport.

<Acid Monomer Copolymerizable with (Meth)Acrylate Monomer>
The first component of the composition may optionally include acid monomers copolymerizable with the (meth)acrylate monomers. If so included, such copolymerizable acids desirably constitute up to 50% by weight, preferably 10-40% by weight, based on the total weight of the (meth)acrylate monomers. For completeness, such monomers should typically be used in the form of their free acids, although it is not precluded to partially or completely neutralize the constituent acid groups of the monomers with a suitable base, provided this does not impair their participation in the copolymerization.

The amount of copolymerizable acid is preferred because if the amount of copolymerizable acid is more than 50%, it may cause corrosion problems and gas generation, while a small amount may cause incomplete curing and reduce initial adhesion.

While not intending to limit the invention, the copolymerizable acid monomer is desirably selected from ethylenically unsaturated carboxylic acids; ethylenically unsaturated sulfonic acids; and vinyl phosphonic acids. Suitable ethylenically unsaturated sulfonic acids are, for example, vinyl sulfonic acid, styrene sulfonic acid, and acrylamidomethylpropane sulfonic acid.

Preferably, the copolymerizable acid of this component comprises or consists of an ethylenically unsaturated carboxylic acid selected from the group consisting of α,β-monoethylenically unsaturated monocarboxylic acids, α,β-monoethylenically unsaturated dicarboxylic acids, C _1- C ₆ alkyl half esters of α,β-monoethylenically unsaturated dicarboxylic acids, α,β-monoethylenically unsaturated tricarboxylic acids, and C _1- C ₆ alkyl esters of α,β-monoethylenically unsaturated tricarboxylic acids having at least one free carboxylic acid group, and mixtures thereof. In particular, the copolymerizable acid of this component comprises or consists of at least one acid selected from methacrylic acid, acrylic acid, itaconic acid, maleic acid, aconitic acid, crotonic acid and fumaric acid.

Further vinyl monomers
Apart from or in addition to the presence of a copolymerizable acid, the first component of the composition may optionally contain vinyl monomers copolymerizable with the (meth)acrylate monomers, said vinyl monomers being styrene monomers such as styrene, vinyltoluene, α-methylstyrene and chlorostyrene; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene and vinylidene fluoride; silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide. , maleimide monomers such as dodecylmaleimide, stearylmaleimide, phenylmaleimide and cyclohexylmaleimide; nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; amide group-containing vinyl monomers such as acrylamide and methacrylamide; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate and vinyl cinnamate; alkenes such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; and vinyl chloride, vinylidene chloride, aryl chloride, aryl alcohol. However, when such vinyl comonomers are included, it is desirable that the amount is less than 40% by weight, preferably less than 20% by weight or less than 10% by weight based on the total weight of the (meth)acrylate monomers.

<Electrolyte>
The first component of the composition comprises 2.5 to 25% by weight of the electrolyte, based on the weight of the first component. The electrolyte may preferably comprise 4 to 23% by weight, such as 5 to 20% by weight, of said first component.

The above amounts of electrolyte are preferred because amounts greater than 25% may provide good release effect but may result in incomplete curing and adversely affect initial adhesive properties, while small amounts, primarily less than 2.5%, may lead to a lack of release effect.

The electrolyte is preferably
wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently selected from hydrogen, C _1-18 alkyl, C _3-18 cycloalkyl, _{C 6-18 aryl, C 7-24 aralkyl, C 2-20 alkenyl , -C (} O) ^{R q} _, -C(O ₎ OH, -CN _{and -NO 2 ,} and ^{R q} _is C _1-6 alkyl.
The compound includes at least one salt having a formula selected from the group consisting of:

For completeness, the terms C1 _{- C18} alkyl, C3 _{- C18} cycloalkyl, C6 _{- C18} aryl, C7 _{- C24} aralkyl, C2 _{- C20} alkenyl expressly include groups in which one or more hydrogen atoms are replaced by a halogen atom (e.g. C1 _{- C18} haloalkyl) or a hydroxyl group (e.g. C1 _{- C18} hydroxyalkyl). In particular, ^R1 , R2, ^R3 , ^{R4 , R5} and ^R6 are preferably independently selected from hydrogen, C1 _{- C12} alkyl, C1 _{- C12} haloalkyl, C1 _{- C12} hydroxyalkyl and C3 _{- C12} cycloalkyl. For example, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be independently selected from hydrogen, C _1- C ₆ alkyl, C _1- C ₆ haloalkyl, and C _1- C ₆ hydroxyalkyl.

There is no intention to limit the counter anion (X ⁻ ) that may be employed in the electrolyte. Exemplary anions may be selected from the following:
Halides;
pseudohalides and halogen-containing compounds of the formula PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₃ ) ₂ N ⁻ , CF ₃ CO ₂ ⁻ and CCl ₃ CO ₂ ⁻ ,
CN- ^{, SCN-} and ^OCN- ;
phenates;
Sulfates, sulfites and sulfonates of the general formula SO ₄ ²⁻ , HSO ₄ ⁻ , SO ₃ ²⁻ , HSO ₃ ⁻ , R ^a OSO ₃ ⁻ and R ^a SO ₃ ⁻ ;
phosphates of the general formula PO ₄ ³⁻ , HPO ₄ ²⁻ , H ₂ PO ₄ ⁻ , R ^a PO ₄ ²⁻ , HR ^a PO ₄ ^— and R ^a R ^b PO ₄ ^— ;
Phosphonates and phosphinates of the general formulae R ^a HPO ₃ ^-- , R ^a R ^b PO ₂ ^-- and R ^a R ^b PO ₃ ^-- ;
Phosphites of the general formula PO ₃ ³⁻ , HPO ₃ ²⁻ , H ₂ PO ₃ ⁻ , R ^a PO ₃ ²⁻ , R ^a HPO ₃ ^— and R ^a R ^b PO ₃ ^— ;
Phosphonites and phosphinites of the general formula R ^a R ^b PO ₂ ⁻ , R ^a HPO ₂ ⁻ , R ^a R ^b PO ⁻ , and R ^a HPO ⁻ ;
a carboxylate anion of the general formula R ^a COO ^- ;
Hydroxycarboxylate and sugar acid anions;
Saccharinates (salts of o-benzoic acid sulfimide);
Borates of the general formula BO ₃ ³⁻ , HBO ₃ ²⁻ , H ₂ BO ₃ ⁻ , R ^a R ^b BO ₃ ⁻ , R ^a HBO ₃ ⁻ , R ^a BO ₃ ²⁻ , B(OR ^a )(OR ^b )(OR ^C )(OR ^d ) ⁻ , B(HSO ₄ ) ⁻ and B(R ^a SO ₄ ) ⁻ ;
boronates of the general formula R ^a BO ₂ ^2- and R ^a R ^b BO ^- ;
Carbonates and carbonate esters of the general formula HCO ₃ ⁻ , CO ₃ ²⁻ and R ^a CO ₃ ⁻ ;
silicates and silicate esters of the general formulae SiO ₄ ⁴⁻ , HSiO ₄ ³⁻ , H ₂ SiO ₄ ²⁻ , H ₃ SiO ₄ ⁻ , R ^a SiO ₄ ³⁻ , R ^a R ^b SiO ₄ ²⁻ , R ^a R ^b R ^c SiO ₄ ⁻ , HR ^a SiO ₄ ²⁻ , H ₂ R ^a SiO ₄ ⁻ and HR ^a R ^b SiO ₄ ⁻ ;
Alkyl- and arylsilanolates of the general formula R ^a SiO ₃ ³⁻ , R ^a R ^b SiO ₂ ²⁻ , R ^{a R b R c} SiO ⁻ , R a R b R ^c SiO ₃ ⁻ , R ^a R ^b R ^c SiO ₂ ⁻ and R ^a R ^b SiO ₃ ²⁻ ;
Pyridinates and pyrimidinates;
・General formula:
carboxylic acid imides, bis(sulfonyl)imides and sulfonylimides of the above formula (I);
・General formula

Methide of;
Alkoxides and aryloxides of the general formula R ^{a O-} ; and
Sulfides, hydrogen sulfides, polysulfides, hydrogen polysulfides and thiolates of the general formula S ²⁻ , HS ⁻ , [S _v ] ²⁻ , [HS _v ] ⁻ and [R ^a S] ⁻
[wherein in the general formula v is a positive integer from 2 to 10.
R ^a , R ^b , R ^c _and R ^d are independently selected from hydrogen, C _1-12 alkyl, C _{5-12 cycloalkyl} , C _{5-12 heterocycloalkyl} , C _6-18 aryl and C _{5-18 heteroaryl .}

Based on the definitions in the above list, preferred anions are selected from the group consisting of halides; pseudohalides and halogen -containing compounds as defined above ; carboxylate anions, in particular formates, acetates, propionates, butyrates and lactates; hydroxycarboxylate anions; pyridinates and pyrimidinates; carboxylic acid imides, bis(sulfonyl)imides and sulfonyl imides; sulfates, in particular methyl sulfate and ethyl sulfate; sulfites; sulfonates, in particular methanesulfonate; and phosphates, in particular dimethyl-phosphate, diethyl-phosphate and di-(2-ethylhexyl)-phosphate.

The electrolyte of the first component is preferably 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium methylsulfate, 1-hexyl-3-methylimidazolium 2-(2-fluoroanilino)-pyridinate, 1-hexyl-3-methylimidazolium imide, 1-butyl-1-methylpyrrolidinium 2-(2-fluoroanilino)-pyridinate, 1-butyl-1-methyl-pyrrolidinium imide, trihexyl(tetradecyl)phospholium 2-(2-fluoroanilino)-pyridinate, cyclohexyltrimethylammonium bis(trifluoromethylsulfonate), N,N-dimethyl(2-hydroxyethyl)ammonium octanoate, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, N-ethyl-N-N-N-N-tetramethylguanidinium trifluoromethanesulfonate, guanidinium trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-hydroxymethylpyridinium ethylsulfate, 1-butyl-1-methylpyrrolidinium Bis(trifluoromethylsulfonyl)imide, 1-butyl-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, 3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-ethyl-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazole, 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium tris(pentafluoroethyl)trifluorophosphate, trihexyl(tetradecyl)phosphonium tetrafluoroborate and mixtures thereof. It is particularly preferred to use at least one of 1-ethyl-3-methylimidazolium methanesulfonate and 1-ethyl-3-methylimidazolium methylsulfate.

The above electrolytes are preferred because they provide the composition with good stability, good initial adhesive strength, and better peeling effect when subjected to potential treatment.

<Solubilizer>
The first component of the two-part (2K) composition necessarily contains a solubilizer, which is usually present in an amount of 0.5 to 20% by weight, based on the weight of the first component. Preferably, the solubilizer constitutes 1 to 15% by weight, for example 1 to 13% by weight, of said first component. The function of the solubilizer is not to improve or change the adhesive properties of the composition, but rather the solubilizer increases the electrical conductivity of the composition of the invention. Furthermore, the solubilizer has the function of promoting the miscibility of the electrolyte in the adhesive composition formed upon mixing of the two components. The solubilizer may or may not form part of the polymer matrix formed upon curing of the adhesive composition, but serves to promote ion migration therein. The solubilizer is thus preferably a polar compound and should desirably be liquid at room temperature.

If the amount of solubilizer exceeds 20%, it may have a detrimental effect on adhesion and curing properties, while small amounts, mainly less than 0.5%, may cause the first component of the composition to become solid, which may inhibit mixing of the first and second components, so these amounts are preferred.

Suitable classes of solubilizers include polyphosphazenes; polymethylene sulfides; polyoxyalkylene glycols; polyethyleneimines; silicone surfactants and fluorinated silicone surfactants, such as fluorinated polysilanes, polyalkylsiloxanes and polyoxyalkylene modified polydimethylsiloxanes; copolymers of functionalized polyalkylsiloxanes and epoxy resins, such as copolymers of functionalized polydimethylsiloxane (PDMS) and epoxy resins; polyhydric alcohols; and sugars.

Ethylene glycol, 1,3-propanediol, cyclohexanediol, hydroquinone, catechol, resorcinol, phloroglucinol, pyrogallol, hydroxyhydroquinone, tris(hydroxymethyl)benzene, tris(hydroxymethyl)benzene with three methyl or ethyl substituents attached to the remaining carbon atom of benzene, isosorbide, isomannide, isoidide, glycerol, cyclohexane-1,2,4-triol, 1,3,5-cyclohexanetriol, pentane-1,2,3-triol, hexane-1,3,5-triol , erythritol, 1,2,4,5-tetrahydroxybenzene, threitol, arabitol, xylitol, ribitol, mannitol, sorbitol, inositol, fructose, glucose, mannose, lactose, 1,1,1-tris(hydroxymethyl)propane, 1,1,1-tris(hydroxymethyl)ethane, di(trimethylolpropane), trimethylolpropane ethoxylate, 2-hydroxymethyl-1,3-propanediol, pentaerythritol aryl ether, and polyhydric alcohols and sugars such as pentaerythritol.

Among the polyoxyalkylene glycols, particular preference may be given to the use of polyoxy(C _{2 -C 3} )alkylene glycols having a weight-average molecular weight of 200 to 10 000 g/mol, for example 200 to 2000 g/mol.

Second part of the two-component (2K) composition
The second component of the two-part composition comprises a first curing agent; an accelerator; and a filler as described hereinabove.

<Curing Agent>
The curing agent must consist of at least one compound having at least two epoxide-reactive groups per molecule, and may include, among others, one or more of: i) at least one polyamine having at least two amine hydrogens reactive with epoxy groups; ii) at least one mercapto compound having at least two mercapto groups reactive with epoxy groups; and iii) at least one Mannich base.

At least one polyamine having at least two amine hydrogens reactive to epoxy groups preferably contains, in particular, primary and/or secondary amine groups and has an equivalent weight per primary or secondary amine group of 150 g/eq. or less, more preferably 125 g/eq. or less.

Suitable polyamines, which may be used alone or in combination, include, but are not limited to, the following:
i) The following examples may be mentioned: aliphatic, cycloaliphatic or arylaliphatic primary diamines: 2,2-dimethyl-1,3-propanediamine; 1,3-pentanediamine (DAMP); 1,5-pentanediamine; 1,5-diamino-2-methylpentane (MPMD); 2-butyl-2-ethyl-1,5-pentanediamine (C11-neodiamine); 1,6-hexanediamine (hexamethylenediamine, HMDA); 2,5-dimethyl-1,6-hexanediamine (Hexamethylenediamine, HMDA); 1,7-heptanediamine; 1,8-octanediamine; 1,9-nonanediamine; 1,10-decanediamine; 1,11-undecanediamine; 1,12-dodecanediamine; 1,2-, 1,3- and 1,4-diaminocyclohexane; bis(4-aminocyclohexyl)methane; bis(4-amino-3-methylcyclohexyl)methane; bis(4-amino-3-ethylcyclohexyl)methane; 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophorone diamine, IPDA); 2- and/or 4-methyl-1,3-diaminocyclohexane; 1,3-bis(aminomethyl)cyclohexane; 1,4-bis(aminomethyl)cyclohexane; 2,5(2,6)-bis(aminomethyl)cyclohexane 1,8-Menthanediamine; 3,9-Bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane; and 1,3-Bis(aminomethyl)benzene (MXDA).
ii) tertiary amine group-containing polyamines having two or three primary aliphatic amine groups, of which the following specific examples may be mentioned: N,N'-bis(aminopropyl)-piperazine;N,N-bis(3-aminopropyl)methylamine;N,N-bis(3-aminopropyl)ethylamine;N,N-bis(3-aminopropyl)propylamine;N,N-bis(3-aminopropyl)cyclohexylamine;N,N-bis(3-aminopropyl)-2-ethylhexylamine;tris(2-aminoethyl)amine;tris(2-aminopropyl)amine;tris(3-aminopropyl)amine; and products from the double cyanoethylation and subsequent reduction of fatty amines derived from natural fatty acids, such as, for example, N,N-bis(3-aminopropyl)dodecylamine and N,N-bis(3-aminopropyl)tallow alkylamine, Triameen® Y12D and Triameen® YT (Akzo It is commercially available under the name Nobel.
iii) Ether group-containing aliphatic primary polyamines, of which the following specific examples may be mentioned: bis(2-aminoethyl)ether; 3,6-dioxaoctane-1,8-diamine; 4,7-dioxadecane-1,10-diamine; 4,7-dioxadecane-2,9-diamine; 4,9-dioxadodecane-1,12-diamine; 5,8-dioxadodecane-3,10-diamine; 4,7,10-trioxatridecane-1,13-diamine and higher oligomers of these diamines; bis(3-aminopropyl)polytetrahydrofuran and other polytetrahydrofurans. Diamines: alicyclic ether group-containing diamines obtained by propoxylation and subsequent amination of 1,4-dimethylolcyclohexane, such as the material commercially available as Jeffamine® RFD-270 (Huntsman); polyoxyalkylene diamines or triamines obtained as products from the amination of polyoxyalkylene diols and polyoxyalkylene triols , which are commercially available under the name Jeffamine® (Huntsman), Polyetheramines (BASF) or PC Amines® (Nitroil). Particular preference may be given to the use of Jeffamine D-230, Jeffamine D-400, Jeffamine D-600, Jeffamine D-2000, Jeffamine D-4000, Jeffamine T-403, Jeffamine T-3000, Jeffamine T-5000, Jeffamine EDR-104, Jeffamine EDR-148 and Jeffamine EDR-176, as well as the corresponding amines from BASF or Nitroil.
iv) primary diamines bearing secondary amine groups, of which the following examples may be mentioned: 3-(2-aminoethyl)aminopropylamine, bis(hexamethylene)triamine (BHMT); diethylenetriamine (DETA); triethylenetetramine (TETA); tetraethylenepentamine (TEPA); pentaethylenehexamine (PEHA); higher homologues of linear polyethyleneamines, such as polyethylenepolyamines with 5 to 7 ethyleneamine units (the so-called "higher ethylenepolyamines"HEPA); dipropylenetriamine (DPTA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N,N'-bis( and N,N'-bis(3-aminopropyl)ethylenediamine (N4-amine), N,N'-bis(3-aminopropyl)-1,4-diaminobutane, N5-(3-aminopropyl)-2-methyl-1,5-pentanediamine, N3-(3-aminopentyl)-1,3-pentanediamine, N5-(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine or N,N'-bis(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine.
v) polyamines containing one primary and at least one secondary amino group, of which the following examples may be mentioned: N-butyl-1,2-ethanediamine; N-hexyl-1,2-ethanediamine; N-(2-ethylhexyl)-1,2-ethanediamine; N-cyclohexyl-1,2-ethanediamine; 4-aminomethyl-piperidine; N-(2-aminoethyl)piperazine; N-methyl-1,3-propanediamine; N-butyl-1,3-propanediamine ;N-(2-ethylhexyl)-1,3-propanediamine;N-cyclohexyl-1,3-propanediamine;3-methylamino-1-pentylamine;3-ethylamino-1-pentylamine;3-cyclohexylamino-1-pentylamine;N-cocoalkyl-1,3-propanediamine and other aliphatic diamines;primary aliphatic diamines with acrylonitrile, maleic or fumaric acid diesters, citraconic acid diesters, acrylic products from Michael type addition reactions of 1:1 molar ratios of acid esters and methacrylic acid esters, acrylic and methacrylic acid amides, and itaconic acid diesters; products from partial reductive alkylation of primary polyamines with aldehydes or ketones, especially the N-monoalkylation products of said polyamines having two primary amine groups, especially 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, BHMT, DETA, TETA, TEPA, DPTA, N3-amines and N4-amines, where the preferred alkyl groups are benzyl, isobutyl, hexyl and 2-ethylhexyl; and partially styrenated polyamines, such as those commercially available as Gaskamine® 240 (Mitsubishi Gas Chemical Company, Inc.).
vi) secondary diamines and, in particular, the aforementioned polyamines having two primary amine groups, in particular 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)-cyclohexane, 1,3-bis(aminomethyl)benzene, BHMT, DETA, TETA, TEPA, DPTA, N,N'-dialkylation products of N3-amines or N4-amines, where preferred alkyl groups are the 2-phenylethyl, benzyl, isobutyl, hexyl and 2-ethylhexyl groups.
vii) The following aromatic polyamines may be mentioned: m- and p-phenylenediamine; 4,4'-, 2,4' and 2,2'-diaminodiphenylmethane;3,3'-dichloro-4,4'-diaminodiphenylmethane(MOCA); 2,4- and 2,6-tolylenediamine; a mixture of 3,5-dimethylthio-2,4-tolylenediamine and 3,5-dimethylthio-2,6-tolylenediamine (available as Ethacure® 300 from the company Albermarle); a mixture of 3,5-diethyl-2,4- tolylenediamine and 3,5-diethyl-2,6-tolylenediamine (DETDA); 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane (M-DEA); 5'-Tetraethyl-2,2'-dichloro-4,4'-diaminodiphenylmethane (M-CDEA); 3,3'-diisopropyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane (M-MIPA); 3,3',5,5'-tetraisopropyl-4,4'-diaminodiphenylmethane (M-DIPA); 4,4'-diaminodiphenyl-sulfone (DDS); 4-amino-N-(4-aminophenyl)benzenesulfonamide; 5,5'-methylenedianthranilic acid; dimethyl-(5,5'-methylenedianthranilate);1,3-propylene-bis(4-aminobenzoate);1,4-butylene-bis(4-aminobenzoate); polytetramethyleneoxide-bis(4-aminobenzoate) (Air available as Versalink® from Chemical Products, Inc.; 1,2-bis(2-aminophenylthio)ethane; 2-methylpropyl-(4-chloro-3,5-diaminobenzoate); and tert. butyl-(4-chloro-3,5-diaminobenzoate).
viii) Polyamidoamines, whose index members (representing constituents) include the reaction products of mono- or polycarboxylic acids or their esters or anhydrides, especially dimeric fatty acids, with aliphatic, cycloaliphatic or aromatic polyamines, such as polyalkyleneamines , e.g., DETA or TETA . Commercially available polyamidoamines include Versamid® 100, 125, 140 and 150 (from Cognis); Aradur® 223, 250 and 848 (from Huntsman); Euretek® 3607 and 530 (from Huntsman); and Beckopox® EH651, EH654, EH655, EH661 and EH663 (from Cytec).

Among the polyamines having at least two primary aliphatic amine groups, preferred are isophorone diamine (IPDA); hexamethylene diamine (HMDA); 1,3-bis(aminomethyl)cyclohexane; 1,4-bis(aminomethyl)cyclohexane; bis(4-aminocyclohexyl)methane; bis(4-amino-3-methylcyclohexyl)methane; NBDA; and ether-containing polyamines having a number average molecular weight (Mn) of up to 500 g/mol. Particularly preferred among the ether-containing polyamines are Jeffamine® D-230 and D-600 (available from Huntsman).

As mentioned above, the compositions of the present invention may optionally contain at least one compound having at least two reactive mercapto groups per molecule. Suitable mercapto-containing compounds that may be used alone or in combination include, but are not limited to, the following:
Liquid mercaptan-terminated polysulfide polymers, commercial examples of which include Thiokol® polymers (available from Morton Thiokol), in particular the types LP-3, LP-33, LP-980, LP-23, LP-55, LP-56, LP-12, LP-31, LP-32 and LP-2; and Thioplast® polymers (from Akzo Nobel), in particular the types G10, G112, G131, G1, G12, G21, G22, G44 and G4.
Mercaptan-terminated polyoxyalkylene ethers obtained by reacting polyoxyalkylene diols and polyoxyalkylene triols with epichlorohydrin or alkylene oxides, followed by reaction with sodium hydrogen sulfide.
Mercaptan-terminated compounds in the form of polyoxyalkylene derivatives known under the trade name Capcure® (from Cognis), in particular the types WR-8, LOF and 3-800.
- Polyesters of thiocarboxylic acids, specific examples of which include pentaerythritol tetramercaptoacetate (PETMP); trimethylolpropane trimercaptoacetate (TMPMP); glycol dimercaptoacetate; and the esterification products of polyoxyalkylene diols and triols, ethoxylated trimethylolpropane and polyester diols with thiocarboxylic acids such as thioglycolic acid and 2- or 3-mercaptopropionic acid .
2,4,6-trimercapto-1,3,5-triazine, 2,2'-(ethylenedioxy)-diethanethiol (triethylene glycol dimercaptan) and/or ethanedithiol.

The use of polyesters of thiocarboxylic acids, in particular at least one of pentaerythritol tetramercaptoacetate (PETMP), trimethylolpropane trimercaptoacetate (TMPMP) and glycol dimercaptoacetate, is found to be preferred.

As mentioned above, the curing agent may include at least one Mannich base. Such compounds may be characterized as including at least one phenalkamine, and in particular a phenalkamine resulting from the condensation of cardanol (CAS No.: 37330-39-5), an aldehyde and an amine. The reactant amine in the condensation reaction is preferably ethylenediamine or diethyltriamine.

Mannich bases and phenalkamines are known in the art and suitable examples include the commercially available phenalkamines Cardolite® NC-541, NC-557, NC-558, NC-566, Lite 2001 and Lite 2002 (available from Cardolite), Aradur® 3440, 3441, 3442 and 3460 (available from Huntsman) and Beckopox® EH614, EH621, EH624, EH628 and EH629 (available from Cytec).

<Accelerator>
Suitable accelerators are materials that promote the reaction of an epoxy group with an epoxy-reactive group, such as the reaction of an amine group or a thiol group with an epoxy group. A specific example involves the use of amine accelerators that function by deprotonating an existing reactive thiol group (-SH) to a thiolate (-S"), which reacts with an epoxy group via nucleophilic ring-opening polymerization.

Without intending to limit the accelerators used in the present invention, the following suitable accelerators may be mentioned: i) acids or compounds hydrolyzable to acids, in particular a) organic carboxylic acids such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid and lactic acid; b) organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid and 4-dodecylbenzenesulfonic acid; c) sulfonic acid esters; d) inorganic acids such as phosphoric acid; e) Lewis acid compounds such as _BF3 amine complexes, SbF f) Bronsted acid compounds such as _{pentafluoroantimonate} complexes; and e) mixtures of the above acids with acid esters; ii) tertiary amines such as 1,4-diazabicyclo[2.2.2]octane, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine, imidazoles (N-methylimidazole, N-vinylimidazole and 1,2-dimethylimidazole). and the salts of such tertiary amines; iii) quaternary ammonium salts, such as, for example, benzyltrimethylammonium chloride; iv) amidines, such as, for example, 1,8-diazabicyclo[5.4.0]undec-7-ene; v) guanidines, such as, for example, 1,1,3,3-tetramethylguanidine; vi) phenols, especially bisphenols; vii) phenolic resins; and viii) phosphites, such as, for example, diphenyl phosphites and triphenyl phosphites.

Those skilled in the art will recognize that accelerator selection is not simply a matter of adding the fastest accelerator. Other factors that are critical in accelerator selection include cost; toxicity; solubility; processing effects such as working time, premature gelation, exothermic decomposition, expansion and outgassing; final properties such as glass transition temperature (Tg), modulus, strength, elongation at break and chemical resistance; regulatory concerns; and ease of use.

In the present invention, it is preferred to employ an accelerator that includes or consists of at least one tertiary amine, at least one amidine, or a mixture thereof. More specifically, the accelerator is preferably selected from the group consisting of imidazole, methylimidazole, benzyldimethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,4-diazabicyclo(2,2,2)octane, and mixtures thereof.

The accelerator is typically present in the composition in an amount of 0.1 to 15% by weight, based on the weight of the second component. The accelerator may preferably constitute 1 to 15% by weight, for example 5 to 15% by weight, of the second component.

These amounts of accelerators are preferred because amounts greater than 15% would result in an excess of accelerator in the composition, which may adversely affect the curing process and adhesive properties, while small amounts, mainly less than 0.1%, may have no physical effect.

<Additives and auxiliary ingredients>
The compositions obtained according to the invention will typically further comprise auxiliaries and additives capable of imparting improved properties to these compositions. For example, the auxiliaries and additives may impart one or more of improved elastic properties; improved elastic recovery; longer effective processing time; faster curing time; and lower residual tack. Independently of one another, such auxiliaries and additives, which may be included in one or both components of the two-part (2K) composition, include: plasticizers; stabilizers, including UV stabilizers; antioxidants; toughening agents; reactive diluents; drying agents; adhesion promoters; germicides; flame retardants; rheological aids; color pigments or color pastes; and/or, optionally, in minor amounts, non-reactive diluents.

Such auxiliaries and additives may be used in any desired combination and proportions, so long as they do not adversely affect the properties and essential characteristics of the composition. With occasional exceptions, these auxiliaries and additives should not collectively exceed 50% by weight of the total composition, and preferably should not account for more than 20% by weight of the composition.

For the sake of completeness, it is noted that, in general, auxiliary materials and additives having reactive groups are formulated in the appropriate component of a two-component (2K) composition to ensure their storage stability. Non-reactive materials can be formulated in either or both of the two components.

A "plasticizer" for the purposes of the present invention is a substance that reduces the viscosity of the composition and thus facilitates its processability, where the plasticizer can constitute up to 10% by weight or up to 5% by weight, based on the total weight of the composition, and is preferably selected from the group consisting of diurethanes, ethers of monofunctional, linear or branched C4-C16 alcohols, such as Cetiol OE (Cognis Deutschland GmbH , Duesseldorf f) , esters of abietic, butyric, thiobutyric, acetic, propionic and citric acids, esters of nitrocellulose and polyvinyl acetate, fatty acid esters, dicarboxylic acid esters, esters of OH-containing or epoxidized fatty acids, glycolic acid esters, benzoic acid esters, phosphate esters, sulfonic acid esters, trimellitic acid esters, polyether plasticizers, such as end-capped polyethylene glycol or polypropylene glycol, polystyrene, hydrocarbon plasticizers, chlorinated paraffins, and mixtures thereof. It is noted that in principle phthalates could be used as plasticizers, however these are not preferred due to their toxicological potential.

For the purposes of the present invention, "stabilizer" is understood to mean an antioxidant, an ultraviolet stabilizer, a heat stabilizer or a hydrolysis stabilizer, where the stabilizers may constitute up to 10% by weight or up to 5% by weight in total, based on the total weight of the composition. Standard commercial examples of stabilizers suitable for use herein include sterically hindered phenols; thioethers; benzotriazoles; benzophenones; benzoates; cyanoacrylates; acrylates; amines of the hindered amine light stabilizer (HALS) type; phosphorus; sulfur; and mixtures thereof.

The compositions of the present invention may optionally include reinforced rubber in the form of core-shell particles dispersed in an epoxy resin matrix. The term "core-shell rubber" or CSR is used according to its standard meaning in the art to indicate a rubber particle core formed by a polymer containing an elastomer or rubbery polymer as a major component, and a shell layer formed by a polymer grafted onto the core. The shell layer partially or entirely covers the surface of the rubber particle core in the graft polymerization step. By weight, the core desirably constitutes at least 50% by weight of the core-shell rubber particle.

The polymeric material of the core desirably has a glass transition temperature (Tg) of 0°C or less, preferably -20°C or less, more preferably -40°C or less, and even more preferably -60°C or less. The polymer of the shell is a non-elastomeric, thermoplastic or thermosetting polymer with a glass transition temperature (Tg) above room temperature, preferably above 30°C, and more preferably above 50°C.

Without intending to limit the invention, the core may include diene homopolymers, such as homopolymers of butadiene or isoprene; diene copolymers, such as copolymers of butadiene or isoprene with one or more ethylenically unsaturated monomers, such as vinyl aromatic monomers, (meth)acrylonitrile, or (meth)acrylates; polymers based on (meth)acrylic acid ester monomers, such as polybutyl acrylate; and polysiloxane elastomers, such as polydimethylsiloxane and crosslinked polydimethylsiloxane.

Also without intending to limit the invention, the shell may be comprised of a polymer or copolymer of one or more monomers selected from (meth)acrylates, such as methyl methacrylate; vinyl aromatic monomers, such as styrene; vinyl cyanides, such as acrylonitrile; unsaturated acids and anhydrides, such as acrylic acid; and (meth)acrylamides. The polymers or copolymers used in the shell may have acid groups ionically crosslinked by metal carboxylate formation, particularly by forming salts of divalent metal cations. The shell polymer or copolymer may also be covalently crosslinked by monomers having two or more double bonds per molecule.

The core-shell rubber particles present preferably have an average particle size (d50) of 10 nm to 300 nm, e.g., 50 nm to 250 nm. Said particle size represents the diameter or largest dimension of a particle in a distribution of particles, and is measured via dynamic light scattering. For completeness, this application does not exclude the presence in the composition of two or more types of core-shell rubber (CSR) particles having different particle size distributions to provide a balance of key properties, including shear strength, peel strength and resin fracture toughness of the resulting cured product.

The core-shell rubber can be selected from commercially available products, examples of which include Paraloid EXL 2650A, EXL 2655 and EXL2691 A (Dow Chemical Company); Clearstrength® XT100 (Arkema Inc.); Kane Ace® MX series, especially MX 120, MX 125, MX 130, MX 136, MX 551, MX553 (Kaneka Corporation); and METABLEN SX-006 (Mitsubishi Rayon Co., Ltd.).

The core-shell rubber particles are desirably contained in the composition in an amount of 0 to 15% by weight, for example 1 to 10% by weight, based on the total weight of the composition.

In alternative expressions of options not intended to be mutually exclusive with those above, the core-shell rubber particles desirably constitute 1 to 30 weight percent, preferably 5 to 25 weight percent, for example 5 to 20 weight percent, of the first component of the composition.

The presence of solvents and non-reactive diluents in the compositions of the invention is also not excluded if this may usefully adjust their viscosity. For example, and by way of example only, the compositions may contain one or more of the following: xylene; 2-methoxyethanol; dimethoxyethanol; 2-ethoxyethanol; 2-propoxyethanol; 2-isopropoxyethanol; 2-butoxyethanol; 2-phenoxyethanol; 2-benzyloxyethanol; benzyl alcohol; ethylene glycol; ethylene glycol dimethyl ether; ethylene glycol diethyl ether; ethylene glycol dibutyl ether; ethylene glycol diphenyl ether; diethylene glycol; diethylene glycol monomethyl ether; diethylene glycol monoethyl ether; diethylene glycol mono-n-butyl ether; diethylene glycol dimethyl ether; diethylene glycol diethyl ether; diethylene glycol di-n-butyryl ether; propylene glycol butyl ether; propylene glycol phenyl ether; dipropylene glycol; dipropylene glycol monomethyl ether; dipropylene glycol dimethyl ether; dipropylene glycol di-n-butyl ether; N-methylpyrrolidone; diphenylmethane; diisopropylnaphthalene; petroleum fractions, such as Solvesso® products (manufactured by Exxon); alkylphenols, such as tert-butylphenol, nonylphenol, dodecylphenol, and 8,11,14-pentadecatrienylphenol; styrenated phenol; bisphenols; aromatic hydrocarbon resins, especially those containing phenolic groups, such as ethoxylated phenol or propoxylated phenol; adipates; sebacates; phthalates; benzoates; organic phosphoric or sulfonic acid esters; and sulfonamides.

Apart from the above, it is preferred that the non-reactive diluents together constitute less than 10% by weight, in particular less than 5% by weight or less than 2% by weight, based on the total weight of the composition.

Exemplary embodiments of two-part (2K) compositions
In an exemplary embodiment of the present invention, a two-part (2K) adhesive composition comprises:
Based on the weight of the first component,
20-45% by weight, preferably 25-40% by weight, of an epoxy resin selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin, cycloaliphatic epoxy resin, and mixtures thereof;
10 to 30 weight percent of a (meth)acrylate monomer, said (meth)acrylate monomer being selected from the group consisting of C1 _{- C6} alkyl esters of (meth)acrylic acid, C3 _{- C12} cycloalkyl esters of (meth)acrylic acid, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, and mixtures thereof;
5-20% by weight of an electrolyte, said electrolyte being selected from 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium methylsulfate and mixtures thereof; and 1-15% by weight of a solubilizer, said solubilizer comprising a polyoxy(C2 _{- C3} ) alkylene glycol having a weight average molecular weight of 200-10000 g/mol, for example 200-2000 g/mol; and a filler;
a first component comprising:
a curing agent consisting of at least one compound having at least two epoxy-reactive groups per molecule, said curing agent comprising at least one polyamine having at least two amine hydrogens reactive towards epoxy groups, said polyamine further comprising primary amine groups and/or secondary amine groups, characterized in that the equivalent weight per primary amine group and/or secondary amine group is 150 g/eq or less;
5-15% by weight of an accelerator, based on the weight of the second component, the accelerator being selected from the group consisting of tertiary amines, quaternary ammonium salts, amidines, guanidines, and mixtures thereof; and a second component comprising a filler.

The applicant has found that the combination of epoxy and acrylic resins in the two-part curable compositions of the present invention provides improved performance and reduced shrinkage, particularly on plastic surfaces. This is achieved by selecting the epoxy resin to provide good chemical resistance, good temperature range, ideal Tg value, good adhesion to metal surfaces and low to near-no shrinkage, and the acrylic resin to provide high T-peel value, good adhesion to plastic surfaces and fast cure.

Methods and Applications
To form a defined two-part (2K) curable composition, the reactive components are mixed together in such a way as to induce its curing. The reactive compounds are desirably mixed under sufficient shear to obtain a homogeneous mixture. It is believed that this can be achieved without special conditions or special equipment. However, suitable mixing equipment may include static mixing equipment; magnetic stir bar equipment; wire whisk equipment; augers; batch mixers; planetary mixers; C.W. Brabender or Banburry® style mixers; and high shear mixers such as blade style blenders and rotating impellers.

For small-scale applications, where volumes generally less than 2 liters are used, the preferred packaging of two-component (2K) compositions is a side-by-side double cartridge or a coaxial cartridge, in which two tubular chambers, typically of equal volume, are arranged side by side or inside each other and sealed by pistons. The drive of these pistons allows the components to be pushed out of the cartridge, advantageously through closely mounted static, speed or dynamic mixers. For large-volume applications, the two components of the composition are advantageously stored in drums or pails. In this case, the two components are pushed out by a hydraulic press, in particular a follower plate, and fed via a pipeline to a mixing device that can ensure a fine and highly homogeneous mixing of the two components. In any case, whatever the package, it is important that the components are arranged in an airtight and moisture-free confinement, so that both components can be stored for a long period of time, ideally for more than 12 months.

Non-limiting examples of two-component dispensing devices and methods that may be suitable for the present invention include those described in U.S. Pat. No. 6,129,244 and U.S. Pat. No. 8,313,006.

The first and second components of the composition are typically mixed in a weight ratio that achieves a desired ratio of epoxy groups to epoxy-reactive groups. By way of example, the weight ratio of the first component to the second component may range from 12:1 to 2:1, preferably from 10:1 to 2:1, such as from 8:1 to 3:1 or from 7:1 to 5:1.

Where applicable, two-part (2K) curable compositions are desirably formulated to exhibit an initial viscosity of less than 200,000 mPa·s, e.g., less than 100,000 mPa·s, at 25°C, measured immediately after mixing, e.g., up to 2 minutes after mixing. Alternatively or in addition to the above viscosity characteristics, two-part (2K) compositions are desirably formulated to be free of bubbles (foam) upon mixing and subsequent curing.

In accordance with the broadest process aspect of the present invention, the above compositions are applied to the material layer(s) and then cured in situ. Prior to applying the composition, it is often desirable to pretreat the relevant surface to remove foreign matter therefrom. If applied, this step may promote subsequent adhesion of the composition thereto. Such treatments are known in the art and may be carried out in a single or multi-step process consisting, for example, of the use of one or more of the following: etching treatment with an acid suitable for the substrate and optionally an oxidizing agent; ultrasonic treatment; plasma treatment, including, for example, chemical plasma treatment, corona treatment, atmospheric plasma treatment and flame plasma treatment; immersion in an aqueous alkaline degreasing bath; treatment with an aqueous cleaning emulsion; treatment with a cleaning solvent such as carbon tetrachloride or trichloroethylene; and rinsing with water, preferably deionized water or pure water. Of these examples, when an aqueous alkaline degreasing bath is used, it is desirable to remove any remaining degreaser on the surface by rinsing the substrate surface with deionized water or pure water.

In some embodiments, adhesion of the compositions of the present invention to a substrate, preferably pretreated, may be promoted by applying a primer thereto. Indeed, a primer composition may be necessary to ensure efficient fixing and/or curing times of the adhesive composition on an inert substrate. Those skilled in the art will be able to select an appropriate primer, and useful references for primer selection include, but are not limited to, U.S. Pat. No. 3,855,040; U.S. Pat. No. 4,731,146; U.S. Pat. No. 4,990,281; U.S. Pat. No. 5,811,473; British Patent No. 2,502,554, and U.S. Pat. No. 6,852,193.

The composition is then preferably applied to the pretreated substrate by conventional application methods such as: brushing; roll coating, for example using a four-coat roll apparatus if the composition is solvent-free or a two-coat roll apparatus if the composition is solvent-borne; doctor blade application; printing methods; and spraying methods such as, but not limited to, air atomized spray, air assisted spray, airless spray, and high volume low pressure spray.

As stated above, the present invention provides an adhesive structure comprising a first material layer having an electrically conductive surface; and a second material layer having an electrically conductive surface, with a cured peelable two-part (2K) adhesive composition as defined herein and in the appended claims disposed between said first and second material layers. To manufacture such a structure, the adhesive composition may be applied to at least one inner surface of the first and/or second material layers, after which the two layers may be subsequently brought into contact, optionally under pressure, such that the electrically peelable hot melt adhesive composition is interposed between the two layers.

It is recommended that the composition be applied to the surface at a wet film thickness of 10-500 μm. Applying thinner layers within this range is more economical and results in a reduced likelihood of harmful thick cured areas. However, great control must be exercised when applying thinner coatings or layers to avoid the formation of discontinuous cured films.

Curing of the coating compositions of the invention typically occurs at temperatures ranging from 40°C to 200°C, preferably from 50°C to 175°C, in particular from 75°C to 175°C. The appropriate temperature depends on the particular compounds present and the desired rate of curing, and can be determined in each individual case by those skilled in the art, if necessary, using simple preliminary tests. Of course, curing at lower temperatures within the aforementioned ranges is advantageous, since it eliminates the need to substantially heat or cool the mixture from the normally prevailing ambient temperature. However, where applicable, the temperature of the mixture formed from the components of the two-part (2K) composition may be raised above the mixing and/or application temperature using conventional methods, including microwave induction.

The present invention will now be described with reference to the accompanying drawings, in which:

As shown in accompanying FIG. 1a, a joint structure is provided in which a layer of cured adhesive (10) is disposed between two conductive substrates (11). A layer of non-conductive material (12) may be disposed on the conductive substrates (11) to form a more complex joint structure, as depicted in FIG. 1b. Each layer of conductive substrate (11) is in electrical contact with a power source (13), which may be a battery or a direct current (DC) AC power source. The positive and negative terminals of the power source (13) are shown in one fixed position, but one skilled in the art will of course recognize that the polarity of the system can be reversed.

The two conductive substrates (11) are shown in the form of layers which may in particular be constituted by metal films; metal sheets; metal meshes or grids, evaporated metal particles, resin materials made conductive by conductive elements disposed in the resin materials, or conductive oxide layers. Exemplary conductive elements include silver filaments, single-walled carbon nanotubes and multi-walled carbon nanotubes. Exemplary conductive oxides include doped indium oxides such as indium tin oxide (ITO); doped zinc oxide; antimony tin oxide; cadmium stannate and zinc stannate. Apart from the choice of conductive material, the skilled person will recognize that the effectiveness of the peeling operation may be reduced if the conductive substrate (11) is in the form of a grid or mesh that limits contact with the layer of cured adhesive (10).

When a voltage is applied between the conductive substrates (11), a current is supplied to the adhesive composition (10) disposed therebetween. This induces an electrochemical reaction at the interface between the substrate (11) and the adhesive composition, which is understood to be oxidative at a positively charged or anodic interface and reductive at a negatively charged or cathodic interface. It is believed that this reaction weakens the adhesive bond between the substrates, allowing the peelable composition to be easily peeled from the substrate.

As shown in Figures 2a and 2b, delamination occurs at the positive electrode interface, which is the interface between the adhesive composition (10) and the conductive surface (11) in electrical contact with the positive electrode. Reversing the direction of the current before separating the substrates can weaken the adhesive bond at the interface of both substrates.

However, it is noted that the composition of the adhesive layer (10) may be adjusted so that delamination occurs simultaneously from either the positive or negative interfaces, or from both. In some embodiments, application of a voltage across both surfaces to form an anodic and cathodic interface results in delamination at both the anodic and cathodic adhesive/substrate interfaces simultaneously. In another embodiment, if the composition is not sensitive to direct current at both interfaces, reverse polarity may be used to delaminate both substrate/adhesive interfaces simultaneously. The current may be applied in any suitable waveform, provided sufficient total time at each polarity is allowed for delamination to occur. Sine waves, square waves, and triangular waves are suitable and may be applied from a controlled voltage source or a controlled current source.

Without intending to limit the invention, it is believed that the peeling operation may be effectively performed when at least one, and preferably both, of the following conditions occur: a) an applied voltage of 0.5 to 200 V; and b) a voltage applied for 1 second to 120 minutes, e.g., 1 second to 60 or 30 minutes. When peeling of the conductive substrate from the cured adhesive is facilitated by the application of a force, e.g., via a weight or spring, it may only require application of a potential on the order of a few seconds.

The following examples are illustrative of the present invention and are not intended to limit the scope of the present invention in any way.

In the examples, the following materials were used:
Cab-O-Sil 720: Fumed silica surface-treated with polydimethylsiloxane (PDMS) (Cabot Corporation)
Casiflux G20: Granular wollastonite (manufactured by Sibelco)
Barbituric acid: pyrimidine-2,4,6(1H,3H,5H)-trione (Merck)
1-Ethyl-3-methylimidazolium methanesulfonate: (TCI America Inc.)
Kane Ace® MX-153: Core-shell rubber particles dispersed in bisphenol A epoxy resin, (Kaneka Corporation)
DER 337: Medium epoxy equivalent weight semi-solid resin based on bisphenol A epoxy, (Olin)
DER 331: Liquid epoxy resin, reaction product of epichlorohydrin and bisphenol A, (Olin)
・Erisys GE-30: Low viscosity high epoxy functional resin (EEW, 135-150g/eq), (manufactured by CVC Thermosets)
EOTMPTA Ac 50: Silica-containing ethoxylated trimethylolpropane triacrylate, (Nissan Chemical Industries)
Jeffamine (registered trademark) D-2000: Ether group-containing aliphatic primary polyamine, (manufactured by Huntsman)
Jeffamine (registered trademark) EDR-176: Ether group-containing aliphatic primary polyamine, (manufactured by Huntsman)
Shieldex AC 3: Anti-rust pigment, (Grace Davison)
PEG400: Polyethylene glycol (Sigma Aldrich)
Albiflex 296: Bisphenol A-epoxy-silicone block copolymer resin, (manufactured by Evonik Industries)
Tris[2-(acryloyloxy)ethyl]isocyanurate: acrylate monomer, (Sigma Aldrich)
Tegopren 5843: Polyether siloxane/100% active silicone surfactant, (Evonik)
4,7,10-trioxa-1,13-tridecanediamine: hardener (Sigma Aldrich)
Tetraethylenepentamine: hardener (manufactured by Acros)
Capcure 3-800: liquid hardener (manufactured by Cognis)
N,N,N',N'-Tetramethyleneethylenediamine: hardener (Merck)
PEGGE (Mn=380): solubilizer, poly(propylene glycol) diglycidyl ether with average Mn≈380, (Sigma Aldrich)

Examples 1, 2 and 3
Part (A) of three two-part (2K) compositions was prepared according to Table 1 below.

Liquid (B) was prepared identically for each of the three two-liquid (2K) compositions according to Table 2 below.

For each example, the parts (A, B) were loaded into separate compartments of a 50 g cartridge and sealed at both ends. The cartridge was then loaded into a cartridge gun and fitted with a mixing tip at the front end. Constant pressure on the trigger forced the two parts into the mixing tip to ensure thorough mixing before application to the substrate as indicated. The weight ratios of parts A and B in the examples were 6.5:1 (Example 1); 7.5:1 (Example 2); and 4.5:1 (Example 3).

The substrates were aluminum (AA6016, 1.25 mm thick) and stainless steel (1.4301, 1.5 mm thick) with various substrate thicknesses, each cut to a size of 2.5 cm x 10 cm (1 inch x 4 inches) for tensile testing.

The tensile lap shear (TLS) test was performed according to the test method described on page 5.

The two-part adhesive composition was applied to the overlapping portions and cured at 150°C for 30 minutes. The samples were then stored in a temperature-controlled room at 25°C and 20% humidity. The bonded structures were then stored for the specified number of days shown in Table 3 below.

The tensile lap shear strength of the substrates described above after the storage period was investigated for both the untreated adhesive substrate and the adhesive substrate treated by applying a constant potential of 50 V to the adhesive layer for 20 minutes. The results are shown in Table 3 below.

Figure 4 shows the results of a lap shear strength test of an aluminum substrate bonded with the curing adhesive of Example 1.

Examples 4, 5, 6, and 7
Four two-part (2K) compositions were prepared as part (A) according to Table 4 below.

Liquid (B) was prepared identically for each of the four two-liquid (2K) compositions according to Table 5 below.

The example compositions and samples were prepared and tested using the same test methods as in Examples 1-3 above. The results are shown in Table 6 below.

Figure 3a shows the peeling when different potentials are applied for 20 minutes, and Figure 3b shows the peeling when 75 V is applied over time.

Example 8
Part (A) of four two-part (2K) compositions was prepared according to Table 7 below.

The example compositions and samples were prepared and tested using the same test methods as in Examples 1-3 above. The results are shown in Table 8 below.

In view of the above description and examples, it will be apparent to those skilled in the art that equivalent modifications are possible without departing from the scope of the claims.

Preferred aspects of the present specification include at least the following.
[1] a) epoxy resin;
b) (meth)acrylate monomers;
c) electrolytes;
d) a solubilizing agent; and
e) filler;
a first component comprising:
a) a curing agent consisting of at least one compound having at least two epoxide reactive groups per molecule;
b) a promoter; and
c) Filler
The second component contains
1. A curable, releasable, two-part hybrid adhesive composition comprising:
[2] The curable and peelable two-component hybrid adhesive composition according to [1], wherein the epoxy resin is selected from the group consisting of bisphenol A type epoxy resins, bisphenol F type epoxy resins, mixtures of bisphenol A type epoxy resins and bisphenol F type epoxy resins, alicyclic epoxy resins, and mixtures thereof, preferably the epoxy resin is bisphenol A type epoxy resin.
[3] The curable and peelable two-part hybrid adhesive composition according to [1] or [2], wherein the epoxy resin is present in an amount of 15 to 60 wt%, preferably 15 to 50 wt%, more preferably 20 to 45 wt%, more preferably 25 to 40 wt%, and even more preferably 28 to 39 wt%, based on the total weight of the first component.
[4] The (meth)acrylate monomer is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, tolyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, acrylate, 2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, isobornyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(meth)acryloyloxypropyltrimethoxysilane, (meth)acrylic acid-ethylene oxide adduct, trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dipentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol tetraacrylate, 1,2-butylene glycol diacrylate, trimethylolpropane ethoxylate tri(meth)acrylate, glyceryl propoxylate tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, tripropylene glycol diacrylate The curable and peelable two-component hybrid adhesive composition according to any one of [1] to [3], wherein the (meth)acrylate monomer is selected from the group consisting of methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, isobornyl methacrylate, isobornyl acrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, and mixtures thereof.
[5] The curable and peelable two-part hybrid adhesive composition according to any of [1] to [4], wherein the (meth)acrylate monomer is present in an amount of 5 to 50 wt%, preferably 7 to 40 wt%, more preferably 10 to 30 wt%, and even more preferably 15 to 27 wt%, based on the total weight of the first component.
[6] The electrolyte is selected from the group consisting of 11-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium methylsulfate, 1-hexyl-3-methylimidazolium 2-(2-fluoroanilino)-pyridinate, 1-hexyl-3-methylimidazolium imide, 1-butyl-1-methylpyrrolidinium 2-(2-fluoroanilino)-pyridinate, 1-butyl-1-methyl-pyrrolidinium imide, trihexyl(tetradecyl)phospholium 2-(2-fluoroanilino)-pyridinate, cyclohexyltrimethylammonium bis(trifluoromethylsulfonyl)imide, and di(2-hydroxyethyl)ammonium trifluoroacetate. , N,N-dimethyl(2-hydroxyethyl)ammonium octanoate, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, N-ethyl-N-N-N-N-tetramethylguanidinium trifluoromethanesulfonate, guanidinium trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-hydroxymethylpyridinium ethyl sulfate, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate , 3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-ethyl-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethyl The curable and peelable two-component hybrid adhesive composition according to any one of [1] to [4], wherein the adhesive is selected from the group consisting of imidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazole, 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium tris(pentafluoroethyl)trifluorophosphate, trihexyl(tetradecyl)phosphonium tetrafluoroborate, and mixtures thereof, and is preferably selected from 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium methylsulfate, and mixtures thereof.
[7] The curable, peelable, two-part hybrid adhesive composition according to any of [1] to [6], wherein the electrolyte is present in a total amount of 2.5 to 25 wt %, preferably 4 to 23 wt %, more preferably 5 to 20 wt %, based on the total weight of the composition.
[8] The curable, peelable two-part hybrid adhesive composition according to any of [1] to [7], wherein the filler of the first component and the filler of the second component may be the same or different and are independently selected from the group consisting of calcium carbonate, calcium oxide, talcum, fumed silica, silica, wollastonite, barium sulfate, glass beads, and mixtures thereof.
[9] The curable and peelable two-part hybrid adhesive composition according to any one of [1] to [8], wherein the filler is present in the first component in an amount of 1 to 40 wt%, preferably 1 to 25 wt%, more preferably 1.5 to 18 wt%, based on the total weight of the first component, and the filler is present in the second component in an amount of 10 to 30 wt%, preferably 15 to 23 wt%, based on the total weight of the second component.
[10] The curable and peelable two-part hybrid adhesive composition according to any one of [1] to [9], wherein the solubilizer is selected from polyphosphazenes; polymethylene sulfides; polyoxyalkylene glycols; polyethyleneimines; silicone surfactants and fluorinated silicone surfactants; copolymers of functionalized polyalkylsiloxanes and epoxy resins; polyhydric alcohols; and sugars.
[11] The curable and peelable two-part hybrid adhesive composition according to any of [1] to [10], wherein the solubilizer is present in an amount of 0.5 to 20 wt %, preferably 1.0 to 15 wt %, more preferably 1.3 to 13 wt %, based on the total weight of the first component.
[12] The curable and peelable two-part hybrid adhesive composition according to any one of [1] to [11], wherein the first component further comprises a copolymerizable acid, preferably in an amount of 1 to 10 wt %, preferably 1.5 to 8 wt %, more preferably 2 to 7 wt %, based on the total weight of the first component.
[13] The curable and peelable two-part hybrid adhesive composition according to any one of [1] to [12], wherein the first component further comprises a toughening agent, preferably in an amount of 1 to 30 wt %, preferably 5 to 25 wt %, more preferably 5 to 21 wt %, based on the total weight of the first component.
[14] The curable, peelable two-part hybrid adhesive composition according to any one of [1] to [13], characterized in that the curing agent comprises at least one polyamine having at least two amine hydrogens reactive towards epoxy groups, the polyamine further comprising primary amine groups and/or secondary amine groups, and having an equivalent weight of 150 g/eq or less per primary amine group or secondary amine group.
[15] The curable and peelable two-part hybrid adhesive composition according to any one of [1] to [14], wherein the accelerator is selected from the group consisting of tertiary amines, quaternary ammonium salts, amidines, guanidines, and mixtures thereof. The accelerator is preferably selected from the group consisting of imidazole, methylimidazole, benzyldimethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,4-diazabicyclo(2,2,2)octane, and mixtures thereof.
[16] The curable and peelable two-part hybrid adhesive composition according to any of [1] to [15], wherein the accelerator is present in an amount of 0.1 to 15 wt%, preferably 1 to 15 wt%, more preferably 5 to 15 wt%, based on the total weight of the second component.
[17] A first material layer having an electrically conductive surface;
a second layer of material having an electrically conductive surface;
Including,
The curable and peelable two-part hybrid adhesive composition according to any one of [1] to [16] is disposed between the first material layer and the second material layer;
Adhesive structure.
[18] 1) applying a voltage across both surfaces to form an anodic interface and a cathodic interface;
and
2) peeling the two surfaces off
Including,
The voltage applied in step 1 is preferably 0.5 to 200 V, and the voltage is preferably applied for 1 second to 60 minutes;
A method for peeling off the bonded structure according to [17].

Claims (18)

a) epoxy resin;
b) (meth)acrylate monomers;
c) electrolytes;
d) a solubilizing agent for solubilizing the electrolyte ; and e) a filler;
a first component comprising:
a) a curing agent consisting of at least one compound having at least two epoxide reactive groups per molecule;
b) an accelerator for the reaction of epoxy groups with epoxide-reactive groups ; and c) a second component comprising a filler,
The solubilizer is present in an amount of 0.5 to 20% by weight based on the total weight of the first component.
A curable, releasable, two-part hybrid adhesive composition. 2. The curable peelable two-part hybrid adhesive composition of claim 1, wherein the epoxy resin is selected from the group consisting of bisphenol A type epoxy resins, bisphenol F type epoxy resins, mixtures of bisphenol A type epoxy resins and bisphenol F type epoxy resins , cycloaliphatic epoxy resins, and mixtures thereof. 3. The curable, peelable, two-part hybrid adhesive composition of claim 1 or 2, wherein the epoxy resin is present in an amount of 15 to 60 wt % , based on the total weight of the first component. The (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, tolyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, isobornyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(meth)acryloyloxypropyltrimethoxysilane, (meth)acrylic acid-ethylene oxide adduct, trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diphenyl ether perfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dipentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol tetraacrylate, 1,2-butylene glycol diacrylate, trimethylol 4. The curable and peelable two-part hybrid adhesive composition according to any one of claims 1 to 3, wherein the dialkyl ether is selected from the group consisting of arylpropane ethoxylate tri(meth)acrylate, glyceryl propoxylate tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol propoxylate di(meth)acrylate, 1,4-butanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate , ethoxylated bisphenol A di(meth)acrylate and mixtures thereof. The curable, peelable, two-part hybrid adhesive composition of any of claims 1 to 4, wherein the (meth)acrylate monomer is present in an amount of 5 to 50 wt% , based on the total weight of the first component. The electrolyte may be 1 -ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium methylsulfate, 1-hexyl-3-methylimidazolium 2-(2-fluoroanilino)-pyridinate, 1-hexyl-3-methylimidazolium imide, 1-butyl-1-methylpyrrolidinium 2-(2-fluoroanilino)-pyridinate, 1-butyl-1-methyl-pyrrolidinium imide, trihexyl(tetradecyl)phospholium 2-(2-fluoroanilino)-pyridinate, cyclohexyltrimethylammonium bis(trifluoromethylsulfonyl)imide, di(2-hydroxyethyl)ammonium trifluoroacetate, N,N-dimethyl(2-hydroxyethyl)ammonium octanoate, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, N-ethyl-N-N-N-N-tetramethylguanidinium trifluoromethanesulfonate, guanidinium trifluoromethanesulfonate, 1-butyl-4-methylpyridinium bromide, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-hydroxymethylpyridinium ethylsulfate, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-methyl Tylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, 3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-ethyl-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium chloride, 1-propyl-3-methylimidazolium iodide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoro 5. The curable and peelable two-part hybrid adhesive composition according to any one of claims 1 to 4, wherein the at least one selected from the group consisting of 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butylimidazole , 1-methylimidazolium tetrafluoroborate, tetrabutylphosphonium tris(pentafluoroethyl)trifluorophosphate, trihexyl(tetradecyl)phosphonium tetrafluoroborate, and mixtures thereof. 7. The curable, peelable, two-part hybrid adhesive composition of claim 1, wherein the electrolyte is present in a total amount of 2.5 to 25 wt % , based on the total weight of the composition. The curable and peelable two-part hybrid adhesive composition according to any one of claims 1 to 7, wherein the filler of the first component and the filler of the second component may be the same or different and are independently selected from the group consisting of calcium carbonate, calcium oxide, talcum, fumed silica, silica, wollastonite, barium sulfate, glass beads, and mixtures thereof. 9. The curable, peelable, two-part hybrid adhesive composition according to any one of claims 1 to 8, wherein the filler is present in the first component in an amount of 1 to 40 wt% , based on the total weight of the first component, and the filler is present in the second component in an amount of 10 to 30 wt% , based on the total weight of the second component. The curable and peelable two-part hybrid adhesive composition according to any one of claims 1 to 9, wherein the solubilizer is selected from polyphosphazenes; polymethylene sulfides; polyoxyalkylene glycols; polyethyleneimines; silicone surfactants and fluorinated silicone surfactants; copolymers of functionalized polyalkylsiloxanes and epoxy resins; polyhydric alcohols; and sugars. The curable, peelable, two-part hybrid adhesive composition of any of claims 1 to 10, wherein the solubilizer is present in an amount of 1.0 to 15 wt% , based on the total weight of the first component. 12. The curable, peelable, two-part hybrid adhesive composition of claim 1, wherein the first component further comprises a copolymerizable acid in an amount of 1 to 10 wt % , based on the total weight of the first component. 13. The curable, peelable, two-part hybrid adhesive composition of any of claims 1 to 12, wherein the first component further comprises a toughening agent in an amount of 1 to 30 wt % , based on the total weight of the first component. The curable and peelable two-part hybrid adhesive composition according to any one of claims 1 to 13, characterized in that the curing agent comprises at least one polyamine having at least two amine hydrogens reactive to epoxy groups, the polyamine further comprising a primary amine group and/or a secondary amine group, and having an equivalent weight of 150 g/eq or less per primary amine group or secondary amine group. 15. The curable, peelable, two-part hybrid adhesive composition of any of claims 1 to 14, wherein the accelerator is selected from the group consisting of tertiary amines, quaternary ammonium salts, amidines, guanidines, and mixtures thereof. 16. The curable, peelable, two-part hybrid adhesive composition of any of claims 1 to 15, wherein the accelerator is present in an amount of 0.1 to 15 wt% , based on the total weight of the second component. a first layer of material having an electrically conductive surface;
a second layer of material having an electrically conductive surface;
Including,
A curable, peelable, two-part hybrid adhesive composition according to any one of claims 1 to 16 is disposed between the first material layer and the second material layer.
Adhesive structure. 1) applying a voltage across both surfaces to form anodic and cathodic interfaces;
and 2) peeling the surfaces apart,
The voltage applied in step 1 is 0.5 to 200 V, and the voltage is applied for 1 second to 60 minutes;
A method for peeling off the bonded structure according to claim 17.